Primality proof for n = 3001:

Take b = 2.

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

5 is prime.
b^((n-1)/5)-1 mod n = 1124, which is a unit, inverse 1909.

(5^3) divides n-1.

(5^3)^2 > n.

n is prime by Pocklington's theorem.