Primality proof for n = 11393:
Take b = 3.
b^(n-1) mod n = 1.
89 is prime.
b^((n-1)/89)-1 mod n = 9674, which is a unit, inverse 9239.
2 is prime.
b^((n-1)/2)-1 mod n = 11391, which is a unit, inverse 5696.
(2^7 * 89) divides n-1.
(2^7 * 89)^2 > n.
n is prime by Pocklington's theorem.