Primality proof for n = 3181:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=53.html>53 is prime.</a>
<br>b^((n-1)/53)-1 mod n = 1274, which is a unit, inverse 2784.
<p><a href=5.html>5 is prime.</a>
<br>b^((n-1)/5)-1 mod n = 1732, which is a unit, inverse 2900.
<p>(5 * 53) divides n-1.
<p>(5 * 53)^2 > n.
<p>n is prime by Pocklington's theorem.