Primality proof for n = 16903:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=313.html>313 is prime.</a>
<br>b^((n-1)/313)-1 mod n = 12266, which is a unit, inverse 1418.
<p>(313) divides n-1.
<p>(313)^2 > n.
<p>n is prime by Pocklington's theorem.