Take b = 2.

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

37 is prime.

b^((n-1)/37)-1 mod n = 233, which is a unit, inverse 2313.

7 is prime.

b^((n-1)/7)-1 mod n = 2379, which is a unit, inverse 2481.

(7 * 37) divides n-1.

(7 * 37)^2 > n.

n is prime by Pocklington's theorem.