Primality proof for n = 766223:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=16657.html>16657 is prime.</a>
<br>b^((n-1)/16657)-1 mod n = 9968, which is a unit, inverse 581816.
<p>(16657) divides n-1.
<p>(16657)^2 > n.
<p>n is prime by Pocklington's theorem.