Primality proof for n = 71993:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=8999.html>8999 is prime.</a>
<br>b^((n-1)/8999)-1 mod n = 255, which is a unit, inverse 12140.
<p>(8999) divides n-1.
<p>(8999)^2 > n.
<p>n is prime by Pocklington's theorem.