Take b = 2.

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

47 is prime.

b^((n-1)/47)-1 mod n = 30028, which is a unit, inverse 5683.

11 is prime.

b^((n-1)/11)-1 mod n = 30210, which is a unit, inverse 8328.

(11^2 * 47) divides n-1.

(11^2 * 47)^2 > n.

n is prime by Pocklington's theorem.