Neighbour primes: Difference between revisions

=={{header|PL/0}}==

|Formatted output isn't PL/0's forté, so this sample just shows each p1 of the p1, p2 neighbours.

<syntaxhighlight lang="pascal">

var n, p1, p2, prime;

procedure isnprime;

var p;

begin

prime := 1;

if n < 2 then prime := 0;

if n > 2 then begin

prime := 0;

if odd( n ) then prime := 1;

p := 3;

while p * p <= n * prime do begin

if n - ( ( n / p ) * p ) = 0 then prime := 0;

p := p + 2;

end

end

end;

begin

p1 := 3;

p2 := 5;

while p2 < 500 do begin

n := ( p1 * p2 ) + 2;

call isnprime;

if prime = 1 then ! p1;

n := p2 + 2;

call isnprime;

while prime = 0 do begin

n := n + 2;

call isnprime;

end;

p1 := p2;

p2 := n;

end

end.

</syntaxhighlight>

{{out}}

<pre>

3

5

7

13

19

67

149

179

229

239

241

269

277

307

313

397

401

419

439

487

</pre>