Primality proof for n = 3203657:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=400457.html>400457 is prime.</a>
<br>b^((n-1)/400457)-1 mod n = 255, which is a unit, inverse 1218646.
<p>(400457) divides n-1.
<p>(400457)^2 > n.
<p>n is prime by Pocklington's theorem.