Primality proof for n = 15661:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=29.html>29 is prime.</a>
<br>b^((n-1)/29)-1 mod n = 11485, which is a unit, inverse 3919.
<p><a href=5.html>5 is prime.</a>
<br>b^((n-1)/5)-1 mod n = 6623, which is a unit, inverse 5363.
<p>(5 * 29) divides n-1.
<p>(5 * 29)^2 > n.
<p>n is prime by Pocklington's theorem.