Hello Monks, I am looking at making a faster, more logical prime number generator than simply brite forcing all available numbers. I am looking into a Miller-Rabin primality test, but I don't know how to do modular exponentiation in perl. Another idea I had was to use the fact that n is prime if (n-1)!+1 is divisable by n. This worked, but the facotorialization created numbers too large for my computer to handle after n=23. If you are interested in this approach, this is the code i used: 
print "Number to test: ";
$prime=<>;


        $t=($prime-1);

sub fac {
        my ($n) = @_;

        if ($n < 2) {
                return $n;
        }
        else {
                return $n *fac($n-1);
        }
}

$r = ((fac($t))+1);


if ($r % $prime) {
        print "not prime\n";
} else {
print "prime\n";
}

[download]
Any help in making a faster, more logical prime number generator than brute-forcing the whole thing would be appreciated. Thanks for the help, monks.

In reply to Prime Numbers by gtozoom

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