Primality proof for n = 389:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=97.html>97 is prime.</a>
<br>b^((n-1)/97)-1 mod n = 15, which is a unit, inverse 26.
<p>(97) divides n-1.
<p>(97)^2 > n.
<p>n is prime by Pocklington's theorem.