Primality proof for n = 7723:
Take b = 2.
b^(n-1) mod n = 1.
13 is prime.
b^((n-1)/13)-1 mod n = 4639, which is a unit, inverse 6238.
11 is prime.
b^((n-1)/11)-1 mod n = 4899, which is a unit, inverse 6331.
(11 * 13) divides n-1.
(11 * 13)^2 > n.
n is prime by Pocklington's theorem.