Primality proof for n = 7717:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=643.html>643 is prime.</a>
<br>b^((n-1)/643)-1 mod n = 4095, which is a unit, inverse 1191.
<p>(643) divides n-1.
<p>(643)^2 > n.
<p>n is prime by Pocklington's theorem.