Safe and Sophie Germain primes: Difference between revisions
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1049 1103 1223 1229 1289 1409 1439 1451 1481 1499
</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
function IsPrime(N: int64): boolean;
{Fast, optimised prime test}
var I,Stop: int64;
begin
if (N = 2) or (N=3) then Result:=true
else if (n <= 1) or ((n mod 2) = 0) or ((n mod 3) = 0) then Result:= false
else
begin
I:=5;
Stop:=Trunc(sqrt(N+0.0));
Result:=False;
while I<=Stop do
begin
if ((N mod I) = 0) or ((N mod (I + 2)) = 0) then exit;
Inc(I,6);
end;
Result:=True;
end;
end;
procedure SophieGermainPrimes(Memo: TMemo);
var I,Cnt: integer;
var S: string;
begin
Cnt:=0;
S:='';
for I:=0 to high(integer) do
if IsPrime(I) then
if IsPrime(2 * I + 1) then
begin
Inc(Cnt);
S:=S+Format('%5D',[I]);
if Cnt>=50 then break;
If (Cnt mod 5)=0 then S:=S+CRLF;
end;
Memo.Lines.Add(S);
Memo.Lines.Add('Count = '+IntToStr(Cnt));
end;
</syntaxhighlight>
{{out}}
<pre>
2 3 5 11 23
29 41 53 83 89
113 131 173 179 191
233 239 251 281 293
359 419 431 443 491
509 593 641 653 659
683 719 743 761 809
911 953 1013 1019 1031
1049 1103 1223 1229 1289
1409 1439 1451 1481 1499
Count = 50
Elapsed Time: 2.520 ms.
</pre>
=={{header|Factor}}==
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