# at that time, primep_rm was called primep, so
sub randprime {
        my $cand;
        do {
                $cand = 10000001 + 2 * int(rand(45000000));
        } until primep($cand);
        $cand;
}
sub randcomposite { # needed for testing
        my $cand;
        do {
                $cand = 10000001 + 2 * int(rand(45000000));
        } until !primep($cand);
        $cand;
}
# ... and the test later ...
if (1) {
        my $F;
        warn "begin";
        open $F, ">", "primes" or die;
        print $F randprime(), "\n" or die for 1 .. 1000;
        close $F or die;
        system q"! factor <primes | cgrep '\d \d'" and die;
        warn "mid";
        open $F, ">", "comps" or die;
        print $F randcomposite(), "\n" or die for 1 .. 1000;
        close $F or die;
        system q"! factor <comps | cgrep -v '\d \d'" and die;
        warn "end";
}