Primality proof for n = 1234853:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=308713.html>308713 is prime.</a>
<br>b^((n-1)/308713)-1 mod n = 15, which is a unit, inverse 1070206.
<p>(308713) divides n-1.
<p>(308713)^2 > n.
<p>n is prime by Pocklington's theorem.