Primality proof for n = 150041:
Take b = 2.
b^(n-1) mod n = 1.
31 is prime.
b^((n-1)/31)-1 mod n = 1966, which is a unit, inverse 62657.
11 is prime.
b^((n-1)/11)-1 mod n = 77599, which is a unit, inverse 22752.
(11^2 * 31) divides n-1.
(11^2 * 31)^2 > n.
n is prime by Pocklington's theorem.