Primality proof for n = 13009:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=271.html>271 is prime.</a>
<br>b^((n-1)/271)-1 mod n = 1879, which is a unit, inverse 3704.
<p>(271) divides n-1.
<p>(271)^2 > n.
<p>n is prime by Pocklington's theorem.