Primality proof for n = 26399:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=197.html>197 is prime.</a>
<br>b^((n-1)/197)-1 mod n = 6307, which is a unit, inverse 13842.
<p>(197) divides n-1.
<p>(197)^2 > n.
<p>n is prime by Pocklington's theorem.