Primality proof for n = 1387801:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=257.html>257 is prime.</a>
<br>b^((n-1)/257)-1 mod n = 527100, which is a unit, inverse 887021.
<p><a href=5.html>5 is prime.</a>
<br>b^((n-1)/5)-1 mod n = 431708, which is a unit, inverse 782333.
<p>(5^2 * 257) divides n-1.
<p>(5^2 * 257)^2 > n.
<p>n is prime by Pocklington's theorem.