Take b = 2.

b^(n-1) mod n = 1.

157 is prime.

b^((n-1)/157)-1 mod n = 34816, which is a unit, inverse 55140.

59 is prime.

b^((n-1)/59)-1 mod n = 22200, which is a unit, inverse 28493.

(59 * 157) divides n-1.

(59 * 157)^2 > n.

n is prime by Pocklington's theorem.