Primality proof for n = 17231:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=1723.html>1723 is prime.</a>
<br>b^((n-1)/1723)-1 mod n = 1023, which is a unit, inverse 3554.
<p>(1723) divides n-1.
<p>(1723)^2 > n.
<p>n is prime by Pocklington's theorem.