Primality proof for n = 250361:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=569.html>569 is prime.</a>
<br>b^((n-1)/569)-1 mod n = 32346, which is a unit, inverse 120103.
<p>(569) divides n-1.
<p>(569)^2 > n.
<p>n is prime by Pocklington's theorem.