Long primes: Difference between revisions

</pre>

=={{header|PureBasic}}==

<lang PureBasic>#MAX=64000

If OpenConsole()=0 : End 1 : EndIf

Dim p.b(#MAX) : FillMemory(@p(),#MAX,#True,#PB_Byte)

For n=2 To Int(Sqr(#MAX))+1 : If p(n) : m=n*n : While m<=#MAX : p(m)=#False : m+n : Wend : EndIf : Next

Procedure.i periodic(v.i)

r=1 : Repeat : r=(r*10)%v : c+1 : If r<=1 : ProcedureReturn c : EndIf : ForEver

EndProcedure

n=500

PrintN(LSet("_",15,"_")+"Long primes upto "+Str(n)+LSet("_",15,"_"))

For i=3 To 500 Step 2

If p(i) And (i-1)=periodic(i)

Print(RSet(Str(i),5)) : c+1 : If c%10=0 : PrintN("") : EndIf

EndIf

Next

PrintN(~"\n")

PrintN("The number of long primes up to:")

PrintN(RSet(Str(n),8)+" is "+Str(c)) : n+n

For i=501 To #MAX+1 Step 2

If p(i) And (i-1)=periodic(i) : c+1 : EndIf

If i>n : PrintN(RSet(Str(n),8)+" is "+Str(c)) : n+n : EndIf

Next

Input()</lang>

{{out}}

<pre>_______________Long primes upto 500_______________

7 17 19 23 29 47 59 61 97 109

113 131 149 167 179 181 193 223 229 233

257 263 269 313 337 367 379 383 389 419

433 461 487 491 499

The number of long primes up to:

500 is 35

1000 is 60

2000 is 116

4000 is 218

8000 is 390

16000 is 716

32000 is 1300

64000 is 2430