Primality proof for n = 27481:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=229.html>229 is prime.</a>
<br>b^((n-1)/229)-1 mod n = 8134, which is a unit, inverse 16369.
<p>(229) divides n-1.
<p>(229)^2 > n.
<p>n is prime by Pocklington's theorem.