open ( SAVE, '>primes.dat' ) or die "Couldn't open primes.dat";

@primes = ( 2 );
$testnumber = 3;

while ( 1 )
{
	foreach $placeholder ( @primes )
	{
		if ( ( $testnumber / $placeholder ) =~ /^[+-]?\d+$/ ) 
		{
			$testnumber = $testnumber + 2;
			next;
		}
		
		if ( $placeholder == $primes[-1] ) 
		{
			push ( @primes, $testnumber );
			print SAVE "$testnumber\n";
		}
		
		next;
	}
}