Primality proof for n = 71263:
Take b = 2.
b^(n-1) mod n = 1.
107 is prime.
b^((n-1)/107)-1 mod n = 5675, which is a unit, inverse 61192.
37 is prime.
b^((n-1)/37)-1 mod n = 24360, which is a unit, inverse 10511.
(37 * 107) divides n-1.
(37 * 107)^2 > n.
n is prime by Pocklington's theorem.