Primality proof for n = 151289:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=18911.html>18911 is prime.</a>
<br>b^((n-1)/18911)-1 mod n = 255, which is a unit, inverse 18392.
<p>(18911) divides n-1.
<p>(18911)^2 > n.
<p>n is prime by Pocklington's theorem.