Primality proof for n = 15773:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=3943.html>3943 is prime.</a>
<br>b^((n-1)/3943)-1 mod n = 15, which is a unit, inverse 13670.
<p>(3943) divides n-1.
<p>(3943)^2 > n.
<p>n is prime by Pocklington's theorem.