View source for Smallest square that begins with n

{{Draft task}}

;Task
Find the smallest &nbsp;(decimal integer)&nbsp; squares that begin with &nbsp; &nbsp; <big> '''n''' </big> &nbsp; &nbsp; for &nbsp; <big> 0 &lt; '''n''' &lt; 50 </big>
<br><br>

=={{header|11l}}==
<syntaxhighlight lang="11l">F firstSquareWithPrefix(n)
   V pfx = String(n)
   L(x) 0..
      V s = String(x * x)
      I s.starts_with(pfx)
         R Int(s)

L(n) 0 <.< 50
   print(firstSquareWithPrefix(n))</syntaxhighlight>

{{out}}
<pre>
1
25
36
4
529
64
729
81
9
100
1156
121
1369
144
1521
16
1764
1849
196
2025
2116
225
2304
2401
25
2601
2704
289
2916
3025
3136
324
3364
3481
35344
36
3721
3844
3969
400
41209
4225
4356
441
45369
4624
4761
484
49
</pre>

=={{header|Action!}}==
<syntaxhighlight lang="action!">CARD FUNC GetNumber(BYTE x)
  CARD i,sq

  i=1
  DO
    sq=i*i
    WHILE sq>x
    DO
      sq==/10
    OD
    IF sq=x THEN
      RETURN (i*i)
    FI
    i==+1
  OD
RETURN (0)

PROC Main()
  BYTE i
  CARD num

  FOR i=1 TO 49
  DO
    num=GetNumber(i)
    PrintC(num) Put(32)
  OD
RETURN</syntaxhighlight>
{{out}}
[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Smallest_square_that_begins_with_n.png Screenshot from Atari 8-bit computer]
<pre>
1 25 36 4 529 64 729 81 9 100 1156 121 1369 144 1521 16 1764 1849 196 2025 2116 225 2304 2401 25 2601 2704 289 2916 3025 3136 324 3364 3481 3585 36 3721 3844 3969 400 4160 4225 4356 441 4529 4624 4761 484 49
</pre>

=={{header|ALGOL 68}}==
<syntaxhighlight lang="algol68">BEGIN # find the smallest square that begins with n for n in 1..49 #
    INT max number = 49;
    [ max number ]INT square; FOR i TO max number DO square[ i ] := 0 OD;
    INT number found := 0;
    FOR i WHILE number found < max number DO
        INT sq = i * i;
        INT v := sq;
        WHILE v > 0 DO
            IF v <= max number THEN
                IF square[ v ] = 0 THEN
                    # found the first square that starts with v #
                    square[ v ]   := sq;
                    number found +:= 1
                FI
            FI;
            v OVERAB 10
        OD
    OD;
    # show the squares #
    FOR i TO max number DO
        print( ( " ", whole( square[ i ], -6 ) ) );
        IF i MOD 10 = 0 THEN print( ( newline ) ) FI
    OD
END</syntaxhighlight>
{{out}}
<pre>
      1     25     36      4    529     64    729     81      9    100
   1156    121   1369    144   1521     16   1764   1849    196   2025
   2116    225   2304   2401     25   2601   2704    289   2916   3025
   3136    324   3364   3481  35344     36   3721   3844   3969    400
  41209   4225   4356    441  45369   4624   4761    484     49
</pre>

=={{header|ALGOL W}}==
<syntaxhighlight lang="algolw">begin % print the lowest square that starts with 1..49        %
    integer MAX_NUMBER;
    MAX_NUMBER := 49;
    begin
        integer array lowest( 1 :: MAX_NUMBER );
        integer       numberFound, n;
        numberFound := 0;
        for i := 1 until MAX_NUMBER do lowest( i ) := 0;
        n := 0;
        while numberFound < MAX_NUMBER do begin
            integer v, n2;
            n := n + 1;
            v := n2 := n * n;
            while v > 0 do begin
                if v <= MAX_NUMBER and lowest( v ) = 0 then begin
                    % found a square that starts with a number in the range %
                    lowest( v ) := n2;
                    numberFound := numberFOund + 1
                end if_v_le_MAX_NUMBER_and_lowest_v_eq_0 ;
                v := v div 10
            end while_v_gt_0
        end while_numberFound_lt_MAX_NUMBER ;
        % show the squares                                     %
        for i := 1 until MAX_NUMBER do begin
            writeon( i_w := 6, s_w := 0, " ", lowest( i ) );
            if i rem 10 = 0 then write()
        end for_i
    end
end.</syntaxhighlight>
{{out}}
<pre>
      1     25     36      4    529     64    729     81      9    100
   1156    121   1369    144   1521     16   1764   1849    196   2025
   2116    225   2304   2401     25   2601   2704    289   2916   3025
   3136    324   3364   3481  35344     36   3721   3844   3969    400
  41209   4225   4356    441  45369   4624   4761    484     49
</pre>

=={{header|AutoHotkey}}==
<syntaxhighlight lang="autohotkey">loop 49
	result .= SS(A_Index) (Mod(A_Index,7)?"`t":"`n")
MsgBox % result
return

SS(n) {
	if (n < 1)
		return
	loop{
		sq := a_index**2
		while (sq > n)
			sq := Format("{:d}", sq/10)
		if (sq = n)
			return a_index**2
	}
}</syntaxhighlight>
{{out}}
<pre>1	25	36	4	529	64	729
81	9	100	1156	121	1369	144
1521	16	1764	1849	196	2025	2116
225	2304	2401	25	2601	2704	289
2916	3025	3136	324	3364	3481	35344
36	3721	3844	3969	400	41209	4225
4356	441	45369	4624	4761	484	49</pre>

=={{header|AWK}}==
<syntaxhighlight lang="awk">
# syntax: GAWK -f SMALLEST_SQUARE_THAT_BEGINS_WITH_N.AWK
# converted from C
BEGIN {
    print("Prefix  n^2    n")
    for (i=1; i<50; i++) {
      x(i)
    }
    exit(0)
}
function x(n,  i,sq) {
    i = 1
    while (1) {
      sq = i * i
      while (sq > n) {
        sq = int(sq/10)
      }
      if (sq == n) {
        printf("%3d %7d %4d\n",n,i*i,i)
        return
      }
      i++
    }
}
</syntaxhighlight>
{{out}}
<pre style="height:45ex">
Prefix  n^2    n
  1       1    1
  2      25    5
  3      36    6
  4       4    2
  5     529   23
  6      64    8
  7     729   27
  8      81    9
  9       9    3
 10     100   10
 11    1156   34
 12     121   11
 13    1369   37
 14     144   12
 15    1521   39
 16      16    4
 17    1764   42
 18    1849   43
 19     196   14
 20    2025   45
 21    2116   46
 22     225   15
 23    2304   48
 24    2401   49
 25      25    5
 26    2601   51
 27    2704   52
 28     289   17
 29    2916   54
 30    3025   55
 31    3136   56
 32     324   18
 33    3364   58
 34    3481   59
 35   35344  188
 36      36    6
 37    3721   61
 38    3844   62
 39    3969   63
 40     400   20
 41   41209  203
 42    4225   65
 43    4356   66
 44     441   21
 45   45369  213
 46    4624   68
 47    4761   69
 48     484   22
 49      49    7
</pre>

=={{header|BASIC}}==
<syntaxhighlight lang="basic">10 FOR I=1 TO 49
20 J=1
30 K=J*J
40 IF K>I THEN K=FIX(K/10): GOTO 40
50 IF K=I THEN PRINT J*J,: GOTO 80
60 J=J+1
70 GOTO 30
80 NEXT I</syntaxhighlight>
{{out}}
<pre> 1             25            36            4             529
 64            729           81            9             100
 1156          121           1369          144           1521
 16            1764          1849          196           2025
 2116          225           2304          2401          25
 2601          2704          289           2916          3025
 3136          324           3364          3481          35344
 36            3721          3844          3969          400
 41209         4225          4356          441           45369
 4624          4761          484           49</pre>

==={{header|BASIC256}}===
<syntaxhighlight lang="freebasic">print "Prefix        n^2           n"
print "-----------------------------"

for i = 1 to 49
    j = 1
    while true
	k = j ^ 2
	while k > i
	    k = int(k / 10)
	end while
	if k = i then
	    print i, j*j, int(sqr(j^2))
	    exit while
	end if
	j += 1
    end while
next i</syntaxhighlight>
{{out}}
<pre>Igual que la entrada de FreeBASIC.</pre>

==={{header|True BASIC}}===
<syntaxhighlight lang="qbasic">PRINT "Prefix           n^2             n"
PRINT "------------------------------------"

FOR i = 1 to 49
    LET N = 1
    DO
       LET j = N ^ 2
       DO WHILE j > i
          LET j = int(j / 10)
       LOOP
       IF j = i then
          PRINT i, N^2, sqr(N^2)
          EXIT DO
       END IF
       LET N = N + 1
    LOOP
NEXT i
END</syntaxhighlight>
{{out}}
<pre>Igual que la entrada de FreeBASIC.</pre>


=={{header|BQN}}==
<syntaxhighlight lang="bqn">Bgn← (⊣≡≠∘⊣↑⊢)○•Fmt
Ssq← ×˜ ⊢{𝕨((Bgn⟜(×˜ ))◶(⊣𝕊1˙+⊢)‿⊢)𝕩}1˙
10‿5⥊@∾Ssq¨1↓↕50</syntaxhighlight>
{{out}}
<pre>┌─                            
╵ @     1     25   36   4     
  529   64    729  81   9     
  100   1156  121  1369 144   
  1521  16    1764 1849 196   
  2025  2116  225  2304 2401  
  25    2601  2704 289  2916  
  3025  3136  324  3364 3481  
  35344 36    3721 3844 3969  
  400   41209 4225 4356 441   
  45369 4624  4761 484  49    
                             ┘</pre>
=={{header|C}}==
<syntaxhighlight lang="c">#include <stdio.h>

void f(int n) {
    int i = 1;
    if (n < 1) {
        return;
    }
    while (1) {
        int sq = i * i;
        while (sq > n) {
            sq /= 10;
        }
        if (sq == n) {
            printf("%3d %9d %4d\n", n, i * i, i);
            return;
        }
        i++;
    }
}

int main() {
    int i;

    printf("Prefix    n^2    n\n");
    printf("");
    for (i = 1; i < 50; i++) {
        f(i);
    }

    return 0;
}</syntaxhighlight>
{{out}}
<pre>Prefix    n^2    n
  1         1    1
  2        25    5
  3        36    6
  4         4    2
  5       529   23
  6        64    8
  7       729   27
  8        81    9
  9         9    3
 10       100   10
 11      1156   34
 12       121   11
 13      1369   37
 14       144   12
 15      1521   39
 16        16    4
 17      1764   42
 18      1849   43
 19       196   14
 20      2025   45
 21      2116   46
 22       225   15
 23      2304   48
 24      2401   49
 25        25    5
 26      2601   51
 27      2704   52
 28       289   17
 29      2916   54
 30      3025   55
 31      3136   56
 32       324   18
 33      3364   58
 34      3481   59
 35     35344  188
 36        36    6
 37      3721   61
 38      3844   62
 39      3969   63
 40       400   20
 41     41209  203
 42      4225   65
 43      4356   66
 44       441   21
 45     45369  213
 46      4624   68
 47      4761   69
 48       484   22
 49        49    7</pre>

=={{header|C#|CSharp}}==
<syntaxhighlight lang="csharp">using System;

class Program
{
    static void Main(string[] args)
    {
        int i, d, s, t, n = 50, c = 1;
        var sw = new int[n];
        for (i = d = s = 1; c < n; i++, s += d += 2)
            for (t = s; t > 0; t /= 10)
                if (t < n && sw[t] < 1)
                    Console.Write("", sw[t] = s, c++);
        Console.Write(string.Join(" ", sw).Substring(2));
    }
}</syntaxhighlight>
{{out}}
Same as F#

=={{header|C++}}==
{{trans|C}}
<syntaxhighlight lang="cpp">#include <iostream>

void f(int n) {
    if (n < 1) {
        return;
    }

    int i = 1;
    while (true) {
        int sq = i * i;
        while (sq > n) {
            sq /= 10;
        }
        if (sq == n) {
            printf("%3d %9d %4d\n", n, i * i, i);
            return;
        }
        i++;
    }
}

int main() {
    std::cout << "Prefix    n^2    n\n";
    for (int i = 0; i < 50; i++) {
        f(i);
    }

    return 0;
}</syntaxhighlight>
{{out}}
<pre>Prefix    n^2    n
  1         1    1
  2        25    5
  3        36    6
  4         4    2
  5       529   23
  6        64    8
  7       729   27
  8        81    9
  9         9    3
 10       100   10
 11      1156   34
 12       121   11
 13      1369   37
 14       144   12
 15      1521   39
 16        16    4
 17      1764   42
 18      1849   43
 19       196   14
 20      2025   45
 21      2116   46
 22       225   15
 23      2304   48
 24      2401   49
 25        25    5
 26      2601   51
 27      2704   52
 28       289   17
 29      2916   54
 30      3025   55
 31      3136   56
 32       324   18
 33      3364   58
 34      3481   59
 35     35344  188
 36        36    6
 37      3721   61
 38      3844   62
 39      3969   63
 40       400   20
 41     41209  203
 42      4225   65
 43      4356   66
 44       441   21
 45     45369  213
 46      4624   68
 47      4761   69
 48       484   22
 49        49    7</pre>

=={{header|CLU}}==
<syntaxhighlight lang="clu">begins_with = proc (n, s: int) returns (bool)
    while n>s do n := n/10 end
    return(n=s)
end begins_with

smallest_square = proc (n: int) returns (int)
    sq: int := 1
    while ~begins_with(sq**2, n) do sq := sq + 1 end
    return(sq**2)
end smallest_square

start_up = proc ()
    po: stream := stream$primary_output()
    col: int := 0
    for i: int in int$from_to(1,49) do
        stream$putright(po, int$unparse(smallest_square(i)), 7)
        col := col + 1
        if col=10 then
            col := 0
            stream$putl(po, "")
        end
    end
    stream$putl(po, "")
end start_up</syntaxhighlight>
{{out}}
<pre>      1     25     36      4    529     64    729     81      9    100
   1156    121   1369    144   1521     16   1764   1849    196   2025
   2116    225   2304   2401     25   2601   2704    289   2916   3025
   3136    324   3364   3481  35344     36   3721   3844   3969    400
  41209   4225   4356    441  45369   4624   4761    484     49</pre>

=={{header|COBOL}}==
<syntaxhighlight lang="cobol">       IDENTIFICATION DIVISION.
       PROGRAM-ID. SMALLEST-SQUARE-BEGINS-WITH-N.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 N            PIC 99.
       01 SQUARE-NO    PIC 999.
       01 SQUARE       PIC 9(5).
       01 OUT-FMT      PIC Z(4)9.

       PROCEDURE DIVISION.
       BEGIN.
           PERFORM SMALLEST-SQUARE THRU SQUARE-START-TEST
               VARYING N FROM 1 BY 1 UNTIL N IS EQUAL TO 50.
           STOP RUN.

       SMALLEST-SQUARE.
           MOVE ZERO TO SQUARE-NO.
       SQUARE-LOOP.
           ADD 1 TO SQUARE-NO.
           MULTIPLY SQUARE-NO BY SQUARE-NO GIVING SQUARE.
       SQUARE-START-TEST.
           IF SQUARE IS GREATER THAN N
               DIVIDE 10 INTO SQUARE
               GO TO SQUARE-START-TEST.
           IF SQUARE IS NOT EQUAL TO N
               GO TO SQUARE-LOOP.
           MULTIPLY SQUARE-NO BY SQUARE-NO GIVING OUT-FMT.
           DISPLAY OUT-FMT.</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>    1
   25
   36
    4
  529
   64
  729
   81
    9
  100
 1156
  121
 1369
  144
 1521
   16
 1764
 1849
  196
 2025
 2116
  225
 2304
 2401
   25
 2601
 2704
  289
 2916
 3025
 3136
  324
 3364
 3481
35344
   36
 3721
 3844
 3969
  400
41209
 4225
 4356
  441
45369
 4624
 4761
  484
   49</pre>

=={{header|Comal}}==
<syntaxhighlight lang="comal">0010 FUNC begins'with(n,s)
0020   WHILE n>s DO n:=n DIV 10
0030   RETURN n=s
0040 ENDFUNC begins'with
0050 //
0060 FUNC smallest'square(a)
0070   sq:=1
0080   WHILE NOT begins'with(sq^2,a) DO sq:+1
0090   RETURN sq^2
0100 ENDFUNC smallest'square
0110 //
0120 ZONE 7
0130 FOR i:=1 TO 49 DO
0140   PRINT smallest'square(i),
0150   IF i MOD 10=0 THEN PRINT
0160 ENDFOR i
0170 PRINT
0180 END</syntaxhighlight>
{{out}}
<pre>1      25     36     4      529    64     729    81     9      100
1156   121    1369   144    1521   16     1764   1849   196    2025
2116   225    2304   2401   25     2601   2704   289    2916   3025
3136   324    3364   3481   35344  36     3721   3844   3969   400
41209  4225   4356   441    45369  4624   4761   484    49</pre>

=={{header|Cowgol}}==
<syntaxhighlight lang="cowgol">include "cowgol.coh";

sub beginsWith(a: uint16, b: uint16): (r: uint8) is
    while a > b loop
        a := a / 10;
    end loop;
    if a == b then r := 1;
    else r := 0;
    end if;
end sub;

sub smallestSquare(n: uint16): (sq: uint16) is
    var sqn: uint16 := 1;
    loop
        sq := sqn * sqn;
        if beginsWith(sq, n) != 0 then
            return;
        end if;
        sqn := sqn + 1;
    end loop;
end sub;

var n: uint16 := 1;
while n < 50 loop
    print_i16(smallestSquare(n));
    print_nl();
    n := n + 1;
end loop;
</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>1
25
36
4
529
64
729
81
9
100
1156
121
1369
144
1521
16
1764
1849
196
2025
2116
225
2304
2401
25
2601
2704
289
2916
3025
3136
324
3364
3481
35344
36
3721
3844
3969
400
41209
4225
4356
441
45369
4624
4761
484
49</pre>

=={{header|D}}==
===Iterative versions===

{{trans|C++}}

<syntaxhighlight lang="d">import std.stdio;

void f(int n) {
    if (n < 1) {
        return;
    }

    int i = 1;

    while (true) {
        int sq = i * i;

        while (sq > n) {
            sq /= 10;
        }
        if (sq == n) {
 			"%3d %9d %4d".writefln(n, i * i, i);
			
            return;
        }

        i++;
     }
}  

void main()
{
	"Prefix    n^2    n".writeln;

	foreach(i ; iota(1, 50)) 
	{
		f(i);
	}
	
}
</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>Prefix    n^2    n
  1         1    1
  2        25    5
  3        36    6
  4         4    2
  5       529   23
  6        64    8
  7       729   27
  8        81    9
  9         9    3
 10       100   10
 11      1156   34
 12       121   11
 13      1369   37
 14       144   12
 15      1521   39
 16        16    4
 17      1764   42
 18      1849   43
 19       196   14
 20      2025   45
 21      2116   46
 22       225   15
 23      2304   48
 24      2401   49
 25        25    5
 26      2601   51
 27      2704   52
 28       289   17
 29      2916   54
 30      3025   55
 31      3136   56
 32       324   18
 33      3364   58
 34      3481   59
 35     35344  188
 36        36    6
 37      3721   61
 38      3844   62
 39      3969   63
 40       400   20
 41     41209  203
 42      4225   65
 43      4356   66
 44       441   21
 45     45369  213
 46      4624   68
 47      4761   69
 48       484   22
 49        49    7
</pre>

===Iterative version 2===
{{trans|Perl}}

<syntaxhighlight lang="d">
import std.stdio, std.range, std.conv, std.string;

// Choose an arbitrary large integer value to make sure brute forcing effective
// FYI 45_369+1 suffices for 0 < n < 50 and anything beyond will do. The output below tells...

const int upperBound = 1_000_000;

bool isTheBeginningOf(int a, int b) {
    return indexOf(to!string(b^^2), to!string(a)) == 0;
}

void main()
{
    foreach(i; iota(1, 50)) {
        foreach(j; iota(upperBound)) {
            if (isTheBeginningOf(i,j)) {
                    writefln("%4d: %4d^2 = %5d", i, j, j^^2 );
                    break;
                }
        }
    }
}
</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>
   1:    1^2 =     1
   2:    5^2 =    25
   3:    6^2 =    36
   4:    2^2 =     4
   5:   23^2 =   529
   6:    8^2 =    64
   7:   27^2 =   729
   8:    9^2 =    81
   9:    3^2 =     9
  10:   10^2 =   100
  11:   34^2 =  1156
  12:   11^2 =   121
  13:   37^2 =  1369
  14:   12^2 =   144
  15:   39^2 =  1521
  16:    4^2 =    16
  17:   42^2 =  1764
  18:   43^2 =  1849
  19:   14^2 =   196
  20:   45^2 =  2025
  21:   46^2 =  2116
  22:   15^2 =   225
  23:   48^2 =  2304
  24:   49^2 =  2401
  25:    5^2 =    25
  26:   51^2 =  2601
  27:   52^2 =  2704
  28:   17^2 =   289
  29:   54^2 =  2916
  30:   55^2 =  3025
  31:   56^2 =  3136
  32:   18^2 =   324
  33:   58^2 =  3364
  34:   59^2 =  3481
  35:  188^2 = 35344
  36:    6^2 =    36
  37:   61^2 =  3721
  38:   62^2 =  3844
  39:   63^2 =  3969
  40:   20^2 =   400
  41:  203^2 = 41209
  42:   65^2 =  4225
  43:   66^2 =  4356
  44:   21^2 =   441
  45:  213^2 = 45369
  46:   68^2 =  4624
  47:   69^2 =  4761
  48:   22^2 =   484
  49:    7^2 =    49
</pre>

=={{header|Draco}}==
<syntaxhighlight lang="draco">proc nonrec prefix(word a, b) bool:
    while a > b do a := a/10 od;
    a = b
corp

proc nonrec findPrefixSquare(word n) word:
    word sq, sqn;
    sqn := 1;
    while
        sq := sqn * sqn;
        not prefix(sq, n)
    do
        sqn := sqn + 1
    od;
    sq
corp

proc nonrec main() void:
    word i, col;
    col := 0;
    for i from 1 upto 49 do
        write(findPrefixSquare(i):7);
        col := col + 1;
        if col = 10 then
            col := 0;
            writeln()
        fi
    od
corp</syntaxhighlight>
{{out}}
<pre>      1     25     36      4    529     64    729     81      9    100
   1156    121   1369    144   1521     16   1764   1849    196   2025
   2116    225   2304   2401     25   2601   2704    289   2916   3025
   3136    324   3364   3481  35344     36   3721   3844   3969    400
  41209   4225   4356    441  45369   4624   4761    484     49</pre>

=={{header|Excel}}==
===LAMBDA===

Binding the name '''firstSquareWithPrefix''' to the following lambda expression in the Name Manager of the Excel WorkBook:

(See [https://www.microsoft.com/en-us/research/blog/lambda-the-ultimatae-excel-worksheet-function/ LAMBDA: The ultimate Excel worksheet function])

{{Works with|Office 365 betas 2021}}
<syntaxhighlight lang="lisp">firstSquareWithPrefix
=LAMBDA(n,
    LET(
        pfx, TEXT(n, "0"),
        lng, LEN(pfx),

        UNTIL(
            LAMBDA(i,
                pfx = MID(TEXT(i ^ 2, "0"), 1, lng)
            )
        )(
            LAMBDA(i, 1 + i)
        )(0) ^ 2
    )
)</syntaxhighlight>

and also assuming the following generic binding in the Name Manager for the WorkBook:

<syntaxhighlight lang="lisp">UNTIL
=LAMBDA(p,
    LAMBDA(f,
        LAMBDA(x,
            IF(p(x),
                x,
                UNTIL(p)(f)(f(x))
            )
        )
    )
)</syntaxhighlight>

{{Out}}
{| class="wikitable" 
|-
|||style="text-align:right; font-family:serif; font-style:italic; font-size:120%;"|fx
! colspan="4" style="text-align:left; vertical-align: bottom; font-family:Arial, Helvetica, sans-serif !important;"|=firstSquareWithPrefix(A2)
|- style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff;"
| 
| A
| B
| C
| D
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 1
|  style="font-weight:bold" | Prefix
|  style="font-style:italic" | Square
|  style="font-weight:bold" | Prefix
|  style="font-style:italic" | Square
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 2
|  style="text-align:right; font-weight:bold" | 1
|  style="text-align:right; background-color:#cbcefb" | 1
|  style="text-align:right; font-weight:bold" | 26
|  style="text-align:right" | 2601
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 3
|  style="text-align:right; font-weight:bold" | 2
|  style="text-align:right" | 25
|  style="text-align:right; font-weight:bold" | 27
|  style="text-align:right" | 2704
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 4
|  style="text-align:right; font-weight:bold" | 3
|  style="text-align:right" | 36
|  style="text-align:right; font-weight:bold" | 28
|  style="text-align:right" | 289
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 5
|  style="text-align:right; font-weight:bold" | 4
|  style="text-align:right" | 4
|  style="text-align:right; font-weight:bold" | 29
|  style="text-align:right" | 2916
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 6
|  style="text-align:right; font-weight:bold" | 5
|  style="text-align:right" | 529
|  style="text-align:right; font-weight:bold" | 30
|  style="text-align:right" | 3025
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 7
|  style="text-align:right; font-weight:bold" | 6
|  style="text-align:right" | 64
|  style="text-align:right; font-weight:bold" | 31
|  style="text-align:right" | 3136
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 8
|  style="text-align:right; font-weight:bold" | 7
|  style="text-align:right" | 729
|  style="text-align:right; font-weight:bold" | 32
|  style="text-align:right" | 324
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 9
|  style="text-align:right; font-weight:bold" | 8
|  style="text-align:right" | 81
|  style="text-align:right; font-weight:bold" | 33
|  style="text-align:right" | 3364
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 10
|  style="text-align:right; font-weight:bold" | 9
|  style="text-align:right" | 9
|  style="text-align:right; font-weight:bold" | 34
|  style="text-align:right" | 3481
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 11
|  style="text-align:right; font-weight:bold" | 10
|  style="text-align:right" | 100
|  style="text-align:right; font-weight:bold" | 35
|  style="text-align:right" | 35344
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 12
|  style="text-align:right; font-weight:bold" | 11
|  style="text-align:right" | 1156
|  style="text-align:right; font-weight:bold" | 36
|  style="text-align:right" | 36
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 13
|  style="text-align:right; font-weight:bold" | 12
|  style="text-align:right" | 121
|  style="text-align:right; font-weight:bold" | 37
|  style="text-align:right" | 3721
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 14
|  style="text-align:right; font-weight:bold" | 13
|  style="text-align:right" | 1369
|  style="text-align:right; font-weight:bold" | 38
|  style="text-align:right" | 3844
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 15
|  style="text-align:right; font-weight:bold" | 14
|  style="text-align:right" | 144
|  style="text-align:right; font-weight:bold" | 39
|  style="text-align:right" | 3969
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 16
|  style="text-align:right; font-weight:bold" | 15
|  style="text-align:right" | 1521
|  style="text-align:right; font-weight:bold" | 40
|  style="text-align:right" | 400
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 17
|  style="text-align:right; font-weight:bold" | 16
|  style="text-align:right" | 16
|  style="text-align:right; font-weight:bold" | 41
|  style="text-align:right" | 41209
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 18
|  style="text-align:right; font-weight:bold" | 17
|  style="text-align:right" | 1764
|  style="text-align:right; font-weight:bold" | 42
|  style="text-align:right" | 4225
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 19
|  style="text-align:right; font-weight:bold" | 18
|  style="text-align:right" | 1849
|  style="text-align:right; font-weight:bold" | 43
|  style="text-align:right" | 4356
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 20
|  style="text-align:right; font-weight:bold" | 19
|  style="text-align:right" | 196
|  style="text-align:right; font-weight:bold" | 44
|  style="text-align:right" | 441
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 21
|  style="text-align:right; font-weight:bold" | 20
|  style="text-align:right" | 2025
|  style="text-align:right; font-weight:bold" | 45
|  style="text-align:right" | 45369
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 22
|  style="text-align:right; font-weight:bold" | 21
|  style="text-align:right" | 2116
|  style="text-align:right; font-weight:bold" | 46
|  style="text-align:right" | 4624
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 23
|  style="text-align:right; font-weight:bold" | 22
|  style="text-align:right" | 225
|  style="text-align:right; font-weight:bold" | 47
|  style="text-align:right" | 4761
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 24
|  style="text-align:right; font-weight:bold" | 23
|  style="text-align:right" | 2304
|  style="text-align:right; font-weight:bold" | 48
|  style="text-align:right" | 484
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 25
|  style="text-align:right; font-weight:bold" | 24
|  style="text-align:right" | 2401
|  style="text-align:right; font-weight:bold" | 49
|  style="text-align:right" | 49
|-
| style="text-align:center; font-family:Arial, Helvetica, sans-serif !important; background-color:#000000; color:#ffffff" | 26
|  style="text-align:right; font-weight:bold" | 25
|  style="text-align:right" | 25
|  style="text-align:right; font-weight:bold" | 50
|  style="text-align:right" | 5041
|}

=={{header|F_Sharp|F#}}==
<syntaxhighlight lang="fsharp">
// Generate emirps. Nigel Galloway: March 25th., 2021
let N=seq{1..0x0FFFFFFF}|>Seq.map(fun n->((*)n>>string)n)|>Seq.cache
let G=let fG n g=n|>Seq.map(fun n->N|>Seq.find(fun i->i.[0..g]=string n)) in seq{yield! fG(seq{1..9}) 0; yield! fG(seq{10..49}) 1}
G|>Seq.iter(printf "%s "); printfn ""
</syntaxhighlight>
{{out}}
<pre>
1 25 36 4 529 64 729 81 9 100 1156 121 1369 144 1521 16 1764 1849 196 2025 2116 225 2304 2401 25 2601 2704 289 2916 3025 3136 324 3364 3481 35344 36 3721 3844 3969 400 41209 4225 4356 441 45369 4624 4761 484 49
</pre>

=={{header|Factor}}==
{{trans|Phix}}
{{works with|Factor|0.99 2021-02-05}}
<syntaxhighlight lang="factor">USING: arrays combinators.short-circuit.smart formatting io
kernel math sequences ;

[let
    50 :> lim
    lim 0 <array> :> res
    1 0 :> ( n! found! )
    [ found lim 1 - < ] [
        n dup * :> n2!
        [ n2 zero? ] [
            { [ n2 lim < ] [ n2 res nth zero? ] } &&
            [ found 1 + found! n n2 res set-nth ] when
            n2 10 /i n2!
        ] until
        n 1 + n!
    ] while
    res rest
]

"Smallest square that begins with..." print
[ 1 + swap [ sq ] keep "%2d: %5d (%3d^2)\n" printf ]
each-index</syntaxhighlight>
{{out}}
<pre style="height:20em">
Smallest square that begins with...
 1:     1 (  1^2)
 2:    25 (  5^2)
 3:    36 (  6^2)
 4:     4 (  2^2)
 5:   529 ( 23^2)
 6:    64 (  8^2)
 7:   729 ( 27^2)
 8:    81 (  9^2)
 9:     9 (  3^2)
10:   100 ( 10^2)
11:  1156 ( 34^2)
12:   121 ( 11^2)
13:  1369 ( 37^2)
14:   144 ( 12^2)
15:  1521 ( 39^2)
16:    16 (  4^2)
17:  1764 ( 42^2)
18:  1849 ( 43^2)
19:   196 ( 14^2)
20:  2025 ( 45^2)
21:  2116 ( 46^2)
22:   225 ( 15^2)
23:  2304 ( 48^2)
24:  2401 ( 49^2)
25:    25 (  5^2)
26:  2601 ( 51^2)
27:  2704 ( 52^2)
28:   289 ( 17^2)
29:  2916 ( 54^2)
30:  3025 ( 55^2)
31:  3136 ( 56^2)
32:   324 ( 18^2)
33:  3364 ( 58^2)
34:  3481 ( 59^2)
35: 35344 (188^2)
36:    36 (  6^2)
37:  3721 ( 61^2)
38:  3844 ( 62^2)
39:  3969 ( 63^2)
40:   400 ( 20^2)
41: 41209 (203^2)
42:  4225 ( 65^2)
43:  4356 ( 66^2)
44:   441 ( 21^2)
45: 45369 (213^2)
46:  4624 ( 68^2)
47:  4761 ( 69^2)
48:   484 ( 22^2)
49:    49 (  7^2)
</pre>

=={{header|FOCAL}}==
<syntaxhighlight lang="focal">01.10 F I=1,49;D 2
01.20 Q

02.10 S N=1
02.20 S S=N*N
02.30 S A=S
02.40 I (A-I)2.7,2.9,2.5
02.50 S A=FITR(A/10)
02.60 G 2.4
02.70 S N=N+1
02.80 G 2.2
02.90 T %5,S,! </syntaxhighlight>
{{out}}
<pre style='height:16em;'>=     1
=    25
=    36
=     4
=   529
=    64
=   729
=    81
=     9
=   100
=  1156
=   121
=  1369
=   144
=  1521
=    16
=  1764
=  1849
=   196
=  2025
=  2116
=   225
=  2304
=  2401
=    25
=  2601
=  2704
=   289
=  2916
=  3025
=  3136
=   324
=  3364
=  3481
= 35344
=    36
=  3721
=  3844
=  3969
=   400
= 41209
=  4225
=  4356
=   441
= 45369
=  4624
=  4761
=   484
=    49</pre>
=={{header|FreeBASIC}}==
<syntaxhighlight lang="freebasic">dim as uinteger ssq(1 to 49), count = 0, curr = 1, curr2
dim as string scurr2
while count < 49
    curr2 = curr^2
    scurr2 = str(curr2)
    for j as uinteger = 1 to 49
        if val(left(scurr2, len(str(j)))) = j and ssq(j) = 0 then
            ssq(j) = curr2
            count += 1
        end if
    next j
    curr += 1
wend

print "Prefix        n^2            n"
print "------------------------------"

for j as uinteger = 1 to 49
    print j, ssq(j), sqr(ssq(j))
next j</syntaxhighlight>
{{out}}<pre style="height:16em">Prefix        n^2            n
------------------------------
1             1              1
2             25             5
3             36             6
4             4              2
5             529            23
6             64             8
7             729            27
8             81             9
9             9              3
10            100            10
11            1156           34
12            121            11
13            1369           37
14            144            12
15            1521           39
16            16             4
17            1764           42
18            1849           43
19            196            14
20            2025           45
21            2116           46
22            225            15
23            2304           48
24            2401           49
25            25             5
26            2601           51
27            2704           52
28            289            17
29            2916           54
30            3025           55
31            3136           56
32            324            18
33            3364           58
34            3481           59
35            35344          188
36            36             6
37            3721           61
38            3844           62
39            3969           63
40            400            20
41            41209          203
42            4225           65
43            4356           66
44            441            21
45            45369          213
46            4624           68
47            4761           69
48            484            22
49            49             7
</pre>

=={{header|Go}}==
{{trans|Wren}}
<syntaxhighlight lang="go">package main

import (
    "fmt"
    "math"
)

func isSquare(n int) bool {
    s := int(math.Sqrt(float64(n)))
    return s*s == n
}

func main() {
    var squares []int
outer:
    for i := 1; i < 50; i++ {
        if isSquare(i) {
            squares = append(squares, i)
        } else {
            n := i
            limit := 10
            for {
                n *= 10
                for j := 0; j < limit; j++ {
                    s := n + j
                    if isSquare(s) {
                        squares = append(squares, s)
                        continue outer
                    }
                }
                limit *= 10
            }
        }
    }
    fmt.Println("Smallest squares that begin with 'n' in [1, 49]:")
    for i, s := range squares {
        fmt.Printf("%5d  ", s)
        if ((i + 1) % 10) == 0 {
            fmt.Println()
        }
    }
    if (len(squares) % 10) != 0 {
        fmt.Println()
    }
}</syntaxhighlight>

{{out}}
<pre>
Smallest squares that begin with 'n' in [1, 49]:
    1     25     36      4    529     64    729     81      9    100  
 1156    121   1369    144   1521     16   1764   1849    196   2025  
 2116    225   2304   2401     25   2601   2704    289   2916   3025  
 3136    324   3364   3481  35344     36   3721   3844   3969    400  
41209   4225   4356    441  45369   4624   4761    484     49  
</pre>

=={{header|Haskell}}==

<syntaxhighlight lang="haskell">import Control.Monad (join)
import Data.List (find, intercalate, isPrefixOf, transpose)
import Data.List.Split (chunksOf)
import Text.Printf (printf)

---------- FIRST SQUARE PREFIXED WITH DIGITS OF N --------

firstSquareWithPrefix :: Int -> Int
firstSquareWithPrefix n = unDigits match
  where
    ds = digits n
    Just match = find (isPrefixOf ds) squareDigits

squareDigits :: [[Int]]
squareDigits = digits . join (*) <$> [0 ..]


--------------------------- TEST -------------------------
main :: IO ()
main =
  putStrLn $
    table "  " $
      chunksOf 10 $
        show . firstSquareWithPrefix <$> [1 .. 49]

------------------------- GENERIC ------------------------

digits :: Int -> [Int]
digits = fmap (read . return) . show

unDigits :: [Int] -> Int
unDigits = foldl ((+) . (10 *)) 0

table :: String -> [[String]] -> String
table gap rows =
  let ws = maximum . fmap length <$> transpose rows
      pw = printf . flip intercalate ["%", "s"] . show
   in unlines $ intercalate gap . zipWith pw ws <$> rows</syntaxhighlight>

{{Out}}
<pre>    1    25    36     4    529    64   729    81     9   100
 1156   121  1369   144   1521    16  1764  1849   196  2025
 2116   225  2304  2401     25  2601  2704   289  2916  3025
 3136   324  3364  3481  35344    36  3721  3844  3969   400
41209  4225  4356   441  45369  4624  4761   484    49</pre>

=={{header|J}}==
<syntaxhighlight lang="j">    *:{.@I. (}.@i. {.@E.&":&>/ *:@i.@*:) 50
1 25 36 4 529 64 729 81 9 100 1156 121 1369 144 1521 16 1764 1849 196 2025 2116 225 2304 2401 25 2601 2704 289 2916 3025 3136 324 3364 3481 35344 36 3721 3844 3969 400 41209 4225 4356 441 45369 4624 4761 484 49</syntaxhighlight>
=={{header|jq}}==
{{works with|jq}}
'''Works with gojq, the Go implementation of jq'''
<syntaxhighlight lang="jq">def smallest_square_beginning_with_n:
  tostring as $n
  | first (range(0; infinite)
           | .*.
           | select(tostring | startswith($n) ))  ;
 
range(1; 50)
| . as $i
| smallest_square_beginning_with_n
| "\(.) is \(sqrt)²"</syntaxhighlight>
{{out}}
<pre>
1 is 1²
25 is 5²
36 is 6²
4 is 2²
529 is 23²
64 is 8²
729 is 27²
81 is 9²
9 is 3²
100 is 10²
1156 is 34²
121 is 11²
1369 is 37²
144 is 12²
1521 is 39²
16 is 4²
1764 is 42²
1849 is 43²
196 is 14²
2025 is 45²
2116 is 46²
225 is 15²
2304 is 48²
2401 is 49²
25 is 5²
2601 is 51²
2704 is 52²
289 is 17²
2916 is 54²
3025 is 55²
3136 is 56²
324 is 18²
3364 is 58²
3481 is 59²
35344 is 188²
36 is 6²
3721 is 61²
3844 is 62²
3969 is 63²
400 is 20²
41209 is 203²
4225 is 65²
4356 is 66²
441 is 21²
45369 is 213²
4624 is 68²
4761 is 69²
484 is 22²
49 is 7²
</pre>

=={{header|Julia}}==
<syntaxhighlight lang="julia">function squaresstartingupto(n, verbose=true)
    res, numfound = zeros(Int, n), 0
    p_int = collect(1:n)
    p_string = string.(p_int)
    for i in 1:typemax(Int)
        sq = i * i
        sq_s = string(sq)
        for (j, s) in enumerate(p_string) 
            if res[j] == 0 && length(sq_s) >= length(s) && sq_s[1:length(s)] == s
                res[j] = sq
                numfound += 1
            end
        end
        if numfound == n
            if verbose
                for p in enumerate(res)
                    print(rpad(p[2], 6), p[1] % 10 == 0 ? "\n" : "")
                end
            end
            break
        end
    end
    return res
end

squaresstartingupto(49)
</syntaxhighlight>{{out}}
<pre>
1     25    36    4     529   64    729   81    9     100   
1156  121   1369  144   1521  16    1764  1849  196   2025  
2116  225   2304  2401  25    2601  2704  289   2916  3025  
3136  324   3364  3481  35344 36    3721  3844  3969  400   
41209 4225  4356  441   45369 4624  4761  484   49  
</pre>

=={{header|MAD}}==
<syntaxhighlight lang="mad">            NORMAL MODE IS INTEGER
            VECTOR VALUES FMT = $I2,3H : ,I6*$
            THROUGH LOOP, FOR I=1, 1, I.G.49
            SQ = 0
FNDSQ       SQ = SQ + 1
            SQR = SQ * SQ
            J = SQR
FNDPFX      WHENEVER J.G.I
                J = J/10
                TRANSFER TO FNDPFX
            END OF CONDITIONAL
            WHENEVER J.NE.I, TRANSFER TO FNDSQ
LOOP        PRINT FORMAT FMT,I,SQR
            END OF PROGRAM</syntaxhighlight>
{{out}}
<pre style='height:50ex;'> 1:      1
 2:     25
 3:     36
 4:      4
 5:    529
 6:     64
 7:    729
 8:     81
 9:      9
10:    100
11:   1156
12:    121
13:   1369
14:    144
15:   1521
16:     16
17:   1764
18:   1849
19:    196
20:   2025
21:   2116
22:    225
23:   2304
24:   2401
25:     25
26:   2601
27:   2704
28:    289
29:   2916
30:   3025
31:   3136
32:    324
33:   3364
34:   3481
35:  35344
36:     36
37:   3721
38:   3844
39:   3969
40:    400
41:  41209
42:   4225
43:   4356
44:    441
45:  45369
46:   4624
47:   4761
48:    484
49:     49</pre>

=={{header|Mathematica}}/{{header|Wolfram Language}}==
<syntaxhighlight lang="mathematica">max = 49;
maxlen = IntegerLength[max];
results = <||>;
Do[
 sq = i^2;
 id = IntegerDigits[sq];
 starts = DeleteDuplicates[Take[id, UpTo[#]] & /@ Range[maxlen]];
 starts //= Map[FromDigits];
 starts //= Select[LessEqualThan[max]];
 Do[
   If[! KeyExistsQ[results, s],
    results = AssociateTo[results, s -> i^2]
    ]
   ,
   {s, starts}
   ]
  If[Length[results] == max, Break[]]
 ,
 {i, 1, \[Infinity]}
 ]
Column[results[#] & /@ Range[49]]</syntaxhighlight>
{{out}}
<pre>1
25
36
4
529
64
729
81
9
100
1156
121
1369
144
1521
16
1764
1849
196
2025
2116
225
2304
2401
25
2601
2704
289
2916
3025
3136
324
3364
3481
35344
36
3721
3844
3969
400
41209
4225
4356
441
45369
4624
4761
484
49</pre>

=={{header|Nim}}==
<syntaxhighlight lang="nim">import strutils

const Max = 49

func starts(k: int): (int, int) =
  ## Return the starting values of "k".
  ## The first one is less than Max.
  ## If the first one is in 1..9, the second one is 0 else it is in 1..9.
  var k = k
  while k > Max: k = k div 10
  result[0] = k
  if k < 10: return
  while k > 9: k = k div 10
  result[1] = k

var squares: array[1..Max, int]   # Maps "n" to the smallest square beginning with "n".
var count = Max                   # Number of squares still to found.
var n = 0

while count > 0:
  inc n
  let n2 = n * n
  let (s1, s2) = n2.starts()
  if squares[s1] == 0:
    squares[s1] = n2
    dec count
  if s2 != 0 and squares[s2] == 0:
    squares[s2] = n2
    dec count

for i, n2 in squares:
  stdout.write ($n2).align(5)
  stdout.write if i mod 7 == 0: '\n' else: ' '</syntaxhighlight>

{{out}}
<pre>    1    25    36     4   529    64   729
   81     9   100  1156   121  1369   144
 1521    16  1764  1849   196  2025  2116
  225  2304  2401    25  2601  2704   289
 2916  3025  3136   324  3364  3481 35344
   36  3721  3844  3969   400 41209  4225
 4356   441 45369  4624  4761   484    49</pre>

=={{header|OCaml}}==
<syntaxhighlight lang="ocaml">let rec is_prefix a b =
  if b > a then is_prefix a (b/10) else a = b

let rec smallest ?(i=1) n =
  let square = i*i in
  if is_prefix n square then square else smallest n ~i:(succ i)

let _ =
  for n = 1 to 49 do
    Printf.printf "%d%c" (smallest n) (if n mod 10 = 0 then '\n' else '\t')
  done</syntaxhighlight>

{{out}}
<pre>1	25	36	4	529	64	729	81	9	100
1156	121	1369	144	1521	16	1764	1849	196	2025
2116	225	2304	2401	25	2601	2704	289	2916	3025
3136	324	3364	3481	35344	36	3721	3844	3969	400
41209	4225	4356	441	45369	4624	4761	484	49	</pre>

=={{header|Perl}}==
<syntaxhighlight lang="perl">use strict;
use warnings;
use constant Inf => 10e12; # arbitrarily large value

for my $n (1..49) {
   do { printf "%2d: %3d^2 = %5d\n", $n, $_, $_**2 and last if $_**2 =~ /^$n/ } for 1..Inf
}</syntaxhighlight>
{{out}}
<pre> 1:   1^2 =     1
 2:   5^2 =    25
 3:   6^2 =    36
 4:   2^2 =     4
 5:  23^2 =   529
 6:   8^2 =    64
 7:  27^2 =   729
 8:   9^2 =    81
 9:   3^2 =     9
10:  10^2 =   100
11:  34^2 =  1156
12:  11^2 =   121
13:  37^2 =  1369
14:  12^2 =   144
26:  51^2 =  2601
27:  52^2 =  2704
28:  17^2 =   289
29:  54^2 =  2916
30:  55^2 =  3025
31:  56^2 =  3136
32:  18^2 =   324
33:  58^2 =  3364
34:  59^2 =  3481
35: 188^2 = 35344
36:   6^2 =    36
37:  61^2 =  3721
38:  62^2 =  3844
39:  63^2 =  3969
40:  20^2 =   400
41: 203^2 = 41209
42:  65^2 =  4225
43:  66^2 =  4356
44:  21^2 =   441
45: 213^2 = 45369
46:  68^2 =  4624
47:  69^2 =  4761
48:  22^2 =   484
49:   7^2 =    49</pre>

=={{header|Phix}}==
<!--<syntaxhighlight lang="phix">(phixonline)-->
 <span style="color: #008080;">constant</span> <span style="color: #000000;">lim</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">49</span>
 <span style="color: #004080;">sequence</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">lim</span><span style="color: #0000FF;">)</span>
 <span style="color: #004080;">integer</span> <span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">found</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
 <span style="color: #008080;">while</span> <span style="color: #000000;">found</span><span style="color: #0000FF;"><</span><span style="color: #000000;">lim</span> <span style="color: #008080;">do</span>
     <span style="color: #004080;">integer</span> <span style="color: #000000;">n2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">*</span><span style="color: #000000;">n</span>
     <span style="color: #008080;">while</span> <span style="color: #000000;">n2</span> <span style="color: #008080;">do</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">n2</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">lim</span> <span style="color: #008080;">and</span> <span style="color: #000000;">res</span><span style="color: #0000FF;">[</span><span style="color: #000000;">n2</span><span style="color: #0000FF;">]=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
             <span style="color: #000000;">found</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
             <span style="color: #000000;">res</span><span style="color: #0000FF;">[</span><span style="color: #000000;">n2</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">n</span>
         <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #000000;">n2</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n2</span><span style="color: #0000FF;">/</span><span style="color: #000000;">10</span><span style="color: #0000FF;">)</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
     <span style="color: #000000;">n</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
 <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">columnize</span><span style="color: #0000FF;">({</span><span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #000000;">lim</span><span style="color: #0000FF;">),</span><span style="color: #7060A8;">sq_power</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">),</span><span style="color: #7060A8;">apply</span><span style="color: #0000FF;">(</span><span style="color: #004600;">true</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">,{{</span><span style="color: #008000;">"(%d^2)"</span><span style="color: #0000FF;">},</span><span style="color: #000000;">res</span><span style="color: #0000FF;">})})</span>
 <span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"Smallest squares that begin with 1..%d:\n%s\n"</span><span style="color: #0000FF;">,</span>
          <span style="color: #0000FF;">{</span><span style="color: #000000;">lim</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">join_by</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">apply</span><span style="color: #0000FF;">(</span><span style="color: #004600;">true</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">,{{</span><span style="color: #008000;">"%2d: %5d %-8s"</span><span style="color: #0000FF;">},</span><span style="color: #000000;">res</span><span style="color: #0000FF;">}),</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #000000;">5</span><span style="color: #0000FF;">)})</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
Smallest squares that begin with 1..49:
 1:     1 (1^2)      11:  1156 (34^2)     21:  2116 (46^2)     31:  3136 (56^2)     41: 41209 (203^2)
 2:    25 (5^2)      12:   121 (11^2)     22:   225 (15^2)     32:   324 (18^2)     42:  4225 (65^2)
 3:    36 (6^2)      13:  1369 (37^2)     23:  2304 (48^2)     33:  3364 (58^2)     43:  4356 (66^2)
 4:     4 (2^2)      14:   144 (12^2)     24:  2401 (49^2)     34:  3481 (59^2)     44:   441 (21^2)
 5:   529 (23^2)     15:  1521 (39^2)     25:    25 (5^2)      35: 35344 (188^2)    45: 45369 (213^2)
 6:    64 (8^2)      16:    16 (4^2)      26:  2601 (51^2)     36:    36 (6^2)      46:  4624 (68^2)
 7:   729 (27^2)     17:  1764 (42^2)     27:  2704 (52^2)     37:  3721 (61^2)     47:  4761 (69^2)
 8:    81 (9^2)      18:  1849 (43^2)     28:   289 (17^2)     38:  3844 (62^2)     48:   484 (22^2)
 9:     9 (3^2)      19:   196 (14^2)     29:  2916 (54^2)     39:  3969 (63^2)     49:    49 (7^2)
10:   100 (10^2)     20:  2025 (45^2)     30:  3025 (55^2)     40:   400 (20^2)
</pre>

=={{header|Picat}}==
===Recursion and string approach===
<syntaxhighlight lang="picat">import util.

main => 
  println([S : N in 1..49, S = smallest_square(N)]).
  
smallest_square(N) = Square =>
  smallest_square(N.to_string,1,Square).
smallest_square(N,S,SS) :-
  SS = S*S,
  find((SS).to_string,N,1,_).
smallest_square(N,S,SS) :-
  smallest_square(N,S+1,SS).</syntaxhighlight>

{{out}}
<pre>[1,25,36,4,529,64,729,81,9,100,1156,121,1369,144,1521,16,1764,1849,196,2025,2116,225,2304,2401,25,2601,2704,289,2916,3025,3136,324,3364,3481,35344,36,3721,3844,3969,400,41209,4225,4356,441,45369,4624,4761,484,49]</pre>

===Iterative===
<syntaxhighlight lang="picat">main => 
  println([S : N in 1..49, S = smallest_square2(N)]).

smallest_square2(N) = Ret =>
  I = 1,
  Found = false,
  while (Found == false)
    Square = I*I,
    while (Square > N)
      Square := Square // 10
    end,
    if Square == N then
      Found := I*I
    end,
    I := I + 1
  end,
  Ret = Found.</syntaxhighlight>
  
{{out}}
<pre>[1,25,36,4,529,64,729,81,9,100,1156,121,1369,144,1521,16,1764,1849,196,2025,2116,225,2304,2401,25,2601,2704,289,2916,3025,3136,324,3364,3481,35344,36,3721,3844,3969,400,41209,4225,4356,441,45369,4624,4761,484,49]</pre>

=={{header|PL/I}}==
<syntaxhighlight lang="pli">smallestSquare: procedure options(main);
    /* does A begin with B? */
    beginsWith: procedure(aa, b) returns(bit);
        declare (a, aa, b) fixed decimal(6);
        do a = aa repeat(a/10) while(a>b); end;
        return(a = b);
    end beginsWith;
    
    /* find smallest square that begins with N */
    smallestSquare: procedure(n) returns(fixed decimal(6));
        declare (n, sqn) fixed decimal(6);
        do sqn = 1 repeat(sqn+1) while(^beginsWith(sqn*sqn, n));
        end;
        return(sqn * sqn);
    end smallestSquare;
    
    declare n fixed;
    do n = 1 to 49;
        put skip list(n,':',smallestSquare(n));
    end;
end smallestSquare;</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>        1 :         1
        2 :        25
        3 :        36
        4 :         4
        5 :       529
        6 :        64
        7 :       729
        8 :        81
        9 :         9
       10 :       100
       11 :      1156
       12 :       121
       13 :      1369
       14 :       144
       15 :      1521
       16 :        16
       17 :      1764
       18 :      1849
       19 :       196
       20 :      2025
       21 :      2116
       22 :       225
       23 :      2304
       24 :      2401
       25 :        25
       26 :      2601
       27 :      2704
       28 :       289
       29 :      2916
       30 :      3025
       31 :      3136
       32 :       324
       33 :      3364
       34 :      3481
       35 :     35344
       36 :        36
       37 :      3721
       38 :      3844
       39 :      3969
       40 :       400
       41 :     41209
       42 :      4225
       43 :      4356
       44 :       441
       45 :     45369
       46 :      4624
       47 :      4761
       48 :       484
       49 :        49</pre>

=={{header|PL/M}}==
<syntaxhighlight lang="pli">100H:
/* CP/M CALLS */
BDOS: PROCEDURE (FN, ARG); DECLARE FN BYTE, ARG ADDRESS; GO TO 5; END BDOS;
EXIT: PROCEDURE; CALL BDOS(0,0); END EXIT;
PRINT: PROCEDURE (S); DECLARE S ADDRESS; CALL BDOS(9,S); END PRINT;

/* PRINT A NUMBER */
PRINT$NUMBER: PROCEDURE (N);
    DECLARE S (6) BYTE INITIAL ('.....$');
    DECLARE (N, P) ADDRESS, C BASED P BYTE;
    P = .S(5);
DIGIT:
    P = P - 1;
    C = N MOD 10 + '0';
    N = N / 10;
    IF N > 0 THEN GO TO DIGIT;
    CALL PRINT(P);
END PRINT$NUMBER;

/* DOES A BEGIN WITH B? */
BEGINS$WITH: PROCEDURE (A, B) BYTE;
    DECLARE (A, B) ADDRESS;
    DO WHILE A > B;
        A = A/10;
    END;
    RETURN A = B;
END BEGINS$WITH;

/* FIND SMALLEST SQUARE THAT BEGINS WITH N */
SMALLEST$SQUARE: PROCEDURE (N) ADDRESS;
    DECLARE (N, SQN, SQ) ADDRESS;
    SQN = 1;
    DO WHILE 1;
        SQ = SQN * SQN;
        IF BEGINS$WITH(SQ, N) THEN
            RETURN SQ;
        SQN = SQN + 1;
    END;
END SMALLEST$SQUARE;

DECLARE N ADDRESS;
DO N = 1 TO 49;
    CALL PRINT$NUMBER(SMALLEST$SQUARE(N));
    CALL PRINT(.(13,10,'$'));
END;
CALL EXIT;
EOF</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>1
25
36
4
529
64
729
81
9
100
1156
121
1369
144
1521
16
1764
1849
196
2025
2116
225
2304
2401
25
2601
2704
289
2916
3025
3136
324
3364
3481
35344
36
3721
3844
3969
400
41209
4225
4356
441
45369
4624
4761
484
49</pre>

=={{header|Python}}==
<syntaxhighlight lang="python">'''First square prefixed by digits of N'''

from itertools import count


# firstSquareWithPrefix :: Int -> Int
def firstSquareWithPrefix(n):
    '''The first perfect square prefixed (in decimal)
       by the decimal digits of N.
    '''
    pfx = str(n)
    lng = len(pfx)
    return int(
        next(
            s for s in (
                str(x * x) for x in count(0)
            )
            if pfx == s[0:lng]
        )
    )


# ------------------------- TEST -------------------------
def main():
    '''First matches for the range [1..49]'''

    print('\n'.join([
        str(firstSquareWithPrefix(x)) for x in range(1, 50)
    ]))


# MAIN ---
if __name__ == '__main__':
    main()</syntaxhighlight>
{{Out}}
<pre>1
25
36
4
529
64
729
81
9
100
1156
121
1369
144
1521
16
1764
1849
196
2025
2116
225
2304
2401
25
2601
2704
289
2916
3025
3136
324
3364
3481
35344
36
3721
3844
3969
400
41209
4225
4356
441
45369
4624
4761
484
49</pre>

=={{header|Quackery}}==
<syntaxhighlight lang="quackery">  [ dup * ]            is squared (   n --> n )

  [ 2dup = iff
      [ 2drop true ]
      done
    2dup < iff
      [ 2drop false ]
      done
    dip [ 10 / ]
    again ]            is starts  ( n n --> b )

  [ times
     [ 0
       [ 1+ 
         dup squared
         i^ 1+
         starts iff
           [ squared
             echo sp ]
           done
         again ] ] ]   is task    (   n -->   )

  49 task</syntaxhighlight>

{{Out}}

<pre>1 25 36 4 529 64 729 81 9 100 1156 121 1369 144 1521 16 1764 1849 196 2025 2116 225 2304 2401 25 2601 2704 289 2916 3025 3136 324 3364 3481 35344 36 3721 3844 3969 400 41209 4225 4356 441 45369 4624 4761 484 49 </pre>

=={{header|Raku}}==
<syntaxhighlight lang="raku" line># 20210319 Raku programming solution

my @needles  = (1..49);
my @haystack = (1..*) Z× (1..*);
# my @haystack = ( 1, 4, -> \a, \b { 2*b - a + 2 } ... * );
# my @haystack = ( 1, { (++$)² } ... * );
for @needles -> \needle {
   for @haystack -> \hay {
      { say needle, " => ", hay and last } if hay.starts-with: needle
   }
}</syntaxhighlight>
{{out}}
<pre>
1 => 1
2 => 25
3 => 36
4 => 4
5 => 529
6 => 64
7 => 729
8 => 81
9 => 9
10 => 100
11 => 1156
12 => 121
13 => 1369
14 => 144
15 => 1521
16 => 16
17 => 1764
18 => 1849
19 => 196
20 => 2025
21 => 2116
22 => 225
23 => 2304
24 => 2401
25 => 25
26 => 2601
27 => 2704
28 => 289
29 => 2916
30 => 3025
31 => 3136
32 => 324
33 => 3364
34 => 3481
35 => 35344
36 => 36
37 => 3721
38 => 3844
39 => 3969
40 => 400
41 => 41209
42 => 4225
43 => 4356
44 => 441
45 => 45369
46 => 4624
47 => 4761
48 => 484
49 => 49
</pre>

As the desired range is so small, there is not much gained by caching the squares. Less efficient, but less verbose:

<syntaxhighlight lang="raku" line>say $_ => ^Inf .map(*²).first: *.starts-with: $_ for 1..49;</syntaxhighlight>

Same output.

=={{header|REXX}}==
A little extra code was added to display the results in a table, &nbsp; the number of columns in the table can be specified.

Also, the output display was generalized so that if a larger number is wider than expected, &nbsp; it won't be truncated.
<syntaxhighlight lang="rexx">/*REXX program  finds and displays  (positive integers)  squares  that begin with  N.   */
numeric digits 20                                /*ensure that large numbers can be used*/
parse arg n cols .                               /*get optional number of primes to find*/
if    n=='' |    n==","  then    n= 50           /*Not specified?   Then assume default.*/
if cols=='' | cols==","  then cols= 10           /* "      "          "     "       "   */
w= 10                                            /*width of a number in any column.     */
say ' index │'center(" smallest squares that begin with  N  < "   n,  1 + cols*(w+1)     )
say '───────┼'center(""                                            ,  1 + cols*(w+1), '─')
#= 0;                  idx= 1                    /*initialize count of found #'s and idx*/
$=;                    nn= n - 1                 /*a list of additive primes  (so far). */
       do j=1  while #<nn                        /*keep searching 'til enough nums found*/
                 do k=1  until pos(j, k * k)==1  /*compute a square of some number.     */
                 end   /*k*/
       #= # + 1                                  /*bump the count of numbers found.     */
                  c= commas(k * k)               /*calculate  K**2 (with commas)  and L */
       $= $ right(c, max(w, length(c) ) )        /*add square to $ list, allow for big N*/
       if #//cols\==0  then iterate              /*have we populated a line of output?  */
       say center(idx, 7)'│'  substr($, 2);  $=  /*display what we have so far  (cols). */
       idx= idx + cols                           /*bump the  index  count for the output*/
       end   /*j*/

if $\==''  then say center(idx, 7)"│"  substr($, 2)  /*possible display residual output.*/
say '───────┴'center(""                                            ,  1 + cols*(w+1), '─')
exit 0                                           /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
commas: parse arg ?;  do jc=length(?)-3  to 1  by -3; ?=insert(',', ?, jc); end;  return ?</syntaxhighlight>
{{out|output|text=&nbsp; when using the default inputs:}}
<pre>
 index │                                   smallest squares that begin with  N  <  50
───────┼───────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │          1         25         36          4        529         64        729         81          9        100
  11   │      1,156        121      1,369        144      1,521         16      1,764      1,849        196      2,025
  21   │      2,116        225      2,304      2,401         25      2,601      2,704        289      2,916      3,025
  31   │      3,136        324      3,364      3,481     35,344         36      3,721      3,844      3,969        400
  41   │     41,209      4,225      4,356        441     45,369      4,624      4,761        484         49  
───────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────
</pre>

=={{header|Ring}}==
<syntaxhighlight lang="ring">
load "stdlib.ring"

see "working..." + nl
see "smallest squares that begin with n:" + nl

row = 0
limit1 = 49
limit2 = 45369

for n = 1 to limit1
    strn = string(n)
    lenn = len(strn)
    for m = 1 to limit2
        floor = sqrt(m)
        bool = (m % floor = 0)
        strm = string(m)
        if left(strm,lenn) = n and bool = 1
           row = row + 1
           see "" + strm + " "
           if row%5 = 0
              see nl
           ok
           exit
        ok
     next
next

see nl + "done..." + nl
</syntaxhighlight>
{{out}}
<pre>
working...
smallest squares that begin with n:
1 25 36 4 529 
64 729 81 9 100 
1156 121 1369 144 1521 
16 1764 1849 196 2025 
2116 225 2304 2401 25 
2601 2704 289 2916 3025 
3136 324 3364 3481 35344 
36 3721 3844 3969 400 
41209 4225 4356 441 45369 
4624 4761 484 49 
done...
</pre>

=={{header|Ruby}}==
{{trans|C}}
<syntaxhighlight lang="ruby">def f(n)
    if n < 1 then
        return
    end

    i = 1
    while true do
        sq = i * i
        while sq > n do
            sq = (sq / 10).floor
        end
        if sq == n then
            print "%3d %9d %4d\n" % [n, i * i, i]
            return
        end
        i = i + 1
    end
end

print("Prefix    n^2    n\n")
print()
for i in 1 .. 49
    f(i)
end</syntaxhighlight>
{{out}}
<pre>Prefix    n^2    n
  1         1    1
  2        25    5
  3        36    6
  4         4    2
  5       529   23
  6        64    8
  7       729   27
  8        81    9
  9         9    3
 10       100   10
 11      1156   34
 12       121   11
 13      1369   37
 14       144   12
 15      1521   39
 16        16    4
 17      1764   42
 18      1849   43
 19       196   14
 20      2025   45
 21      2116   46
 22       225   15
 23      2304   48
 24      2401   49
 25        25    5
 26      2601   51
 27      2704   52
 28       289   17
 29      2916   54
 30      3025   55
 31      3136   56
 32       324   18
 33      3364   58
 34      3481   59
 35     35344  188
 36        36    6
 37      3721   61
 38      3844   62
 39      3969   63
 40       400   20
 41     41209  203
 42      4225   65
 43      4356   66
 44       441   21
 45     45369  213
 46      4624   68
 47      4761   69
 48       484   22
 49        49    7</pre>

=={{header|SenseTalk}}==
<syntaxhighlight lang="sensetalk">repeat with n = 1 to 49
	put smallestNumberWhoseSquareBeginsWith(n) into num
	put !"[[n]]:  [[num squared]] is [[num]] squared"
end repeat

to handle smallestNumberWhoseSquareBeginsWith n
	repeat forever
		if the counter squared begins with n then return the counter
	end repeat
end handler
</syntaxhighlight>
{{out}}
<pre>
1:  1 is 1 squared
2:  25 is 5 squared
3:  36 is 6 squared
4:  4 is 2 squared
5:  529 is 23 squared
6:  64 is 8 squared
7:  729 is 27 squared
8:  81 is 9 squared
9:  9 is 3 squared
10:  100 is 10 squared
11:  1156 is 34 squared
12:  121 is 11 squared
13:  1369 is 37 squared
14:  144 is 12 squared
15:  1521 is 39 squared
16:  16 is 4 squared
17:  1764 is 42 squared
18:  1849 is 43 squared
19:  196 is 14 squared
20:  2025 is 45 squared
21:  2116 is 46 squared
22:  225 is 15 squared
23:  2304 is 48 squared
24:  2401 is 49 squared
25:  25 is 5 squared
26:  2601 is 51 squared
27:  2704 is 52 squared
28:  289 is 17 squared
29:  2916 is 54 squared
30:  3025 is 55 squared
31:  3136 is 56 squared
32:  324 is 18 squared
33:  3364 is 58 squared
34:  3481 is 59 squared
35:  35344 is 188 squared
36:  36 is 6 squared
37:  3721 is 61 squared
38:  3844 is 62 squared
39:  3969 is 63 squared
40:  400 is 20 squared
41:  41209 is 203 squared
42:  4225 is 65 squared
43:  4356 is 66 squared
44:  441 is 21 squared
45:  45369 is 213 squared
46:  4624 is 68 squared
47:  4761 is 69 squared
48:  484 is 22 squared
49:  49 is 7 squared
</pre>

=={{header|Sidef}}==
<syntaxhighlight lang="ruby">1..49 -> map {|n|
    [n, n.isqrt..Inf -> first {|j| Str(j**2).starts_with(n) }]
}.slices(5).each {|a|
    say a.map { '%2d: %5d %-8s' % (_[0], _[1]**2, "(#{_[1]}^2)") }.join(' ')
}</syntaxhighlight>
{{out}}
<pre>
 1:     1 (1^2)     2:    25 (5^2)     3:    36 (6^2)     4:     4 (2^2)     5:   529 (23^2)  
 6:    64 (8^2)     7:   729 (27^2)    8:    81 (9^2)     9:     9 (3^2)    10:   100 (10^2)  
11:  1156 (34^2)   12:   121 (11^2)   13:  1369 (37^2)   14:   144 (12^2)   15:  1521 (39^2)  
16:    16 (4^2)    17:  1764 (42^2)   18:  1849 (43^2)   19:   196 (14^2)   20:  2025 (45^2)  
21:  2116 (46^2)   22:   225 (15^2)   23:  2304 (48^2)   24:  2401 (49^2)   25:    25 (5^2)   
26:  2601 (51^2)   27:  2704 (52^2)   28:   289 (17^2)   29:  2916 (54^2)   30:  3025 (55^2)  
31:  3136 (56^2)   32:   324 (18^2)   33:  3364 (58^2)   34:  3481 (59^2)   35: 35344 (188^2) 
36:    36 (6^2)    37:  3721 (61^2)   38:  3844 (62^2)   39:  3969 (63^2)   40:   400 (20^2)  
41: 41209 (203^2)  42:  4225 (65^2)   43:  4356 (66^2)   44:   441 (21^2)   45: 45369 (213^2) 
46:  4624 (68^2)   47:  4761 (69^2)   48:   484 (22^2)   49:    49 (7^2)   
</pre>

# Numbered list item
=={{header|TXR}}==

===One Pass Through Squares===

In this solution we avoid calculating squares; no multiplication occurs in the code.
We generate successive squares using a recurrence relation. 

We also avoid doing a <code>starts-with</code> test using digits. Rather, we take each successive square and begin repeatedly dividing it by 10, with a truncating division. Whenever the quotient fits into the range 0 to 49 (valid index for our output table) we check whether the entry at that position is <code>nil</code>. If so, this is the smallest square which begins with the digits of that position and we put it into the table there. When 49 numbers have been placed, indicated by an incrementing counter, the algorithm ends. The <code>[out 0]</code> entry is left null.

<syntaxhighlight lang="txrlisp">(for ((cnt 49) (n 1) (sq 1) (st 3) (out (vector 50)))
     ((plusp cnt) (each ((x 1..50))
                    (put-line (pic "## ########" x [out x]))))
     ((inc sq st) (inc st 2) (inc n))
  (for ((xsq sq)) ((plusp xsq)) ((set xsq (trunc xsq 10)))
    (when (and (< xsq 50) (null [out xsq]))
      (set [out xsq] sq)
      (dec cnt))))
</syntaxhighlight>

{{out}}

<pre> 1        1
 2       25
 3       36
 4        4
 5      529
 6       64
 7      729
 8       81
 9        9
10      100
11     1156
12      121
13     1369
14      144
15     1521
16       16
17     1764
18     1849
19      196
20     2025
21     2116
22      225
23     2304
24     2401
25       25
26     2601
27     2704
28      289
29     2916
30     3025
31     3136
32      324
33     3364
34     3481
35    35344
36       36
37     3721
38     3844
39     3969
40      400
41    41209
42     4225
43     4356
44      441
45    45369
46     4624
47     4761
48      484
49       49</pre>

===Terse===

The following inefficient-but-terse solution produces the same output:

<syntaxhighlight lang="txrlisp">(each ((n 1..50))
  (flow [mapcar* square 1]
        (find-if (opip digits (starts-with (digits n))))
        (pic "## ########" n)
        put-line))</syntaxhighlight>

===Loopy===

{{trans|BASIC}}

<syntaxhighlight lang="txrlisp">(each ((i 1..50))
  (block search
    (each ((j 1))
      (for ((k (square j)))
           ((> k i) (when (eql k i)
                      (put-line (pic "## ########" i (square j)))
                      (return-from search)))
           ((set k (trunc k 10)))))))</syntaxhighlight>

=={{header|VTL-2}}==
<syntaxhighlight lang="vtl2">10 N=1
15 C=0
20 S=0
30 S=S+1
40 Q=S*S
50 R=Q
60 #=80
70 R=R/10
80 #=N<R*70
90 #=N=R=0*30
100 ?=Q
110 C=C+1
120 #=C/7*0+%=0*150
130 $=9
140 #=160
150 ?=""
160 N=N+1
170 #=N<50*20</syntaxhighlight>
{{out}}
<pre>1	25	36	4	529	64	729
81	9	100	1156	121	1369	144
1521	16	1764	1849	196	2025	2116
225	2304	2401	25	2601	2704	289
2916	3025	3136	324	3364	3481	35344
36	3721	3844	3969	400	41209	4225
4356	441	45369	4624	4761	484	49</pre>

=={{header|Wren}}==
{{libheader|Wren-seq}}
{{libheader|Wren-fmt}}
<syntaxhighlight lang="ecmascript">import "/seq" for Lst
import "/fmt" for Fmt

var isSquare = Fn.new { |n|
    var s = n.sqrt.floor
    return s * s == n
}

var squares = []
for (i in 1..49) {
    if (isSquare.call(i)) {
        squares.add(i)
    } else {
        var n = i
        var limit = 10
        while (true) {
            n = n * 10
            var found = false
            for (j in 0...limit) {
                var s = n + j
                if (isSquare.call(s)) {
                    squares.add(s)
                    found = true
                    break
                }
            }
            if (found) break
            limit = limit * 10
        }
    }
}
System.print("Smallest squares that begin with 'n' in [1, 49]:")
for (chunk in Lst.chunks(squares, 10)) Fmt.print("$5d", chunk)</syntaxhighlight>

{{out}}
<pre>
Smallest squares that begin with 'n' in [1, 49]:
    1    25    36     4   529    64   729    81     9   100  
 1156   121  1369   144  1521    16  1764  1849   196  2025  
 2116   225  2304  2401    25  2601  2704   289  2916  3025  
 3136   324  3364  3481 35344    36  3721  3844  3969   400  
41209  4225  4356   441 45369  4624  4761   484    49  
</pre>

=={{header|XPL0}}==
<syntaxhighlight lang="xpl0">int Count, N, M, Q;
[Count:= 0;
for N:= 1 to 49 do
   [M:= 1;
   loop [Q:= M*M;
        while Q > N do          \whittle off low digits
            Q:= Q/10;
        if Q = N then
            [IntOut(0, M*M);
            Count:= Count+1;
            if rem(Count/10) = 0 then CrLf(0) else ChOut(0, 9\tab\);
            quit;
            ];
        M:= M+1;
        ];
   ];
]</syntaxhighlight>

{{out}}
<pre>
1       25      36      4       529     64      729     81      9       100
1156    121     1369    144     1521    16      1764    1849    196     2025
2116    225     2304    2401    25      2601    2704    289     2916    3025
3136    324     3364    3481    35344   36      3721    3844    3969    400
41209   4225    4356    441     45369   4624    4761    484     49      
</pre>

=={{header|Yabasic}}==
{{trans|BASIC}}
<syntaxhighlight lang="yabasic">// Rosetta Code problem: http://rosettacode.org/wiki/Smallest_square_that_begins_with_n
// by Galileo, 05/2022

FOR I = 1 TO 49
    J = 1
    DO
        K = J * J
        WHILE K > I K = INT(K / 10) : WEND
        IF K = I PRINT J * J, : BREAK
        J = J + 1
    LOOP
NEXT I</syntaxhighlight>
{{out}}
<pre>1       25      36      4       529     64      729     81      9       100     1156    121     1369    144     1521    16      1764    1849    196     2025    2116    225     2304    2401    25      2601    2704    289     2916    3025    3136    324     3364    3481    35344   36      3721    3844    3969    400     41209   4225    4356    441     45369   4624    4761    484     49      ---Program done, press RETURN---</pre>

=={{header|Zig}}==
<syntaxhighlight lang="zig">pub fn beginsWith(a: u16, b: u16) bool {
    var aa = a;
    while (aa > b) aa /= 10;
    return aa == b;
}

pub fn smallestSquare(n: u16) u16 {
    var sqn: u16 = 1;
    while (true) : (sqn += 1) {
        var sq = sqn * sqn;
        if (beginsWith(sq, n)) return sq;
    }
}

pub fn main() !void {
    const stdout = @import("std").io.getStdOut().writer();
    var n: u16 = 1;
    while (n < 50) : (n += 1) {
        try stdout.print("{d}\n", .{smallestSquare(n)});
    }
}</syntaxhighlight>
{{out}}
<pre style='height:50ex;'>1
25
36
4
529
64
729
81
9
100
1156
121
1369
144
1521
16
1764
1849
196
2025
2116
225
2304
2401
25
2601
2704
289
2916
3025
3136
324
3364
3481
35344
36
3721
3844
3969
400
41209
4225
4356
441
45369
4624
4761
484
49</pre>