Unprimeable numbers: Difference between revisions
Content added Content deleted
(→{{header|Wren}}: Now uses Wren-math module.) |
(→{{header|REXX}}: simplified parts of the program, optimized for speed.) |
||
| Line 1,775: | Line 1,775: | ||
if !.new then iterate j /*This new number a prime? " " */ |
if !.new then iterate j /*This new number a prime? " " */ |
||
end /*e_*/ |
end /*e_*/ |
||
meat= right(j, L-1) /*obtain the last L-1 digits of J. */ |
|||
/* [↑] examine a new 1st digit of J. */ |
/* [↑] examine a new 1st digit of J. */ |
||
do f_=0 for 10; new= (f_||meat) + 0 /*obtain a different number (than J).*/ |
do f_=0 for 10; new= (f_||meat) + 0 /*obtain a different number (than J).*/ |
||
| Line 1,794: | Line 1,792: | ||
if #<=n then $$= $$ commas(j) /*maybe add unprimeable # to $$ list.*/ |
if #<=n then $$= $$ commas(j) /*maybe add unprimeable # to $$ list.*/ |
||
if #==x then $.ox= commas(j) /*assign the Xth unprimeable number.*/ |
if #==x then $.ox= commas(j) /*assign the Xth unprimeable number.*/ |
||
parse var j '' -1 _ /*obtain the right─most dec digit of J.*/ |
|||
if $._==. then $._= j /*the 1st unprimeable # that ends in _.*/ |
if $._==. then $._= j /*the 1st unprimeable # that ends in _.*/ |
||
if $.3==. then iterate; if $.7==. then iterate /*test if specific #'s found.*/ |
if $.3==. then iterate; if $.7==. then iterate /*test if specific #'s found.*/ |
||
| Line 1,814: | Line 1,812: | ||
th:procedure;parse arg x;return x||word('th st nd rd',1+(x//10)*(x//100%10\==1)*(x//10<4)) |
th:procedure;parse arg x;return x||word('th st nd rd',1+(x//10)*(x//100%10\==1)*(x//10<4)) |
||
/*──────────────────────────────────────────────────────────────────────────────────────*/ |
/*──────────────────────────────────────────────────────────────────────────────────────*/ |
||
genP: @.1=2; |
genP: @.1=2; @.2=3; @.3=5; @.4=7; @.5=11; @.6= 13; @.7=17; @.8=19; @.9=23; @.10=29; #p=10 |
||
!.=0; |
!.=0; !.2=1; !.3=1; !.5=1; !.7=1; !.11=1; !.13=1; !.17=1; !.19=1; !.23=1; !.29=1 |
||
do lim=100 until lim*lim>=hp |
do lim=100 until lim*lim>=hp /*only keep primes up to the sqrt(hp). */ |
||
end /*lim*/ /* [↑] find limit for storing primes. */ |
|||
do j=@.#p+2 by 2 to hp /*only find odd primes from here on. */ |
|||
parse var j '' -1 _;if _==5 then iterate /* |
parse var j '' -1 _;if _==5 then iterate /*Get last digit; is last digit a "5" ?*/ |
||
if j// |
if j// 3==0 then iterate /*is J divisible by 3? Then not prime*/ |
||
if j// 7==0 then iterate /* " " " " 7? " " " */ |
|||
if j//11==0 then iterate /* " " " " 11? " " " */ |
if j//11==0 then iterate /* " " " " 11? " " " */ |
||
if j//13==0 then iterate /* |
if j//13==0 then iterate /* " " " " 13? " " " */ |
||
if j//17==0 then iterate /* " " " " 17? " " " */ |
|||
if j//19==0 then iterate /* " " " " 19? " " " */ |
|||
if j//23==0 then iterate /* " " " " 23? " " " */ |
|||
if j//29==0 then iterate /* " " " " 29? " " " */ |
|||
do k=11 while k*k<=j /*divide by some generated odd primes. */ |
|||
if j // @.k==0 then iterate j /*Is J divisible by P? Then not prime*/ |
if j // @.k==0 then iterate j /*Is J divisible by P? Then not prime*/ |
||
end /*k*/ /* [↓] a prime (J) has been found. */ |
end /*k*/ /* [↓] a prime (J) has been found. */ |
||
#p= #p+1; if #p<=lim then @.#p=j; !.j=1 /*bump prime count; assign prime to @.*/ |
|||
end /*j*/; |
end /*j*/; return</lang> |
||
{{out|output|text= when using the default inputs:}} |
{{out|output|text= when using the default inputs:}} |
||