Primality proof for n = 513928823:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=661.html>661 is prime.</a>
<br>b^((n-1)/661)-1 mod n = 28519645, which is a unit, inverse 65192971.
<p><a href=599.html>599 is prime.</a>
<br>b^((n-1)/599)-1 mod n = 314420, which is a unit, inverse 135654522.
<p>(599 * 661) divides n-1.
<p>(599 * 661)^2 > n.
<p>n is prime by Pocklington's theorem.