Primality proof for n = 60509:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=2161.html>2161 is prime.</a>
<br>b^((n-1)/2161)-1 mod n = 17531, which is a unit, inverse 33442.
<p>(2161) divides n-1.
<p>(2161)^2 > n.
<p>n is prime by Pocklington's theorem.