Primality proof for n = 7949:

Take b = 2.

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

1987 is prime.
b^((n-1)/1987)-1 mod n = 15, which is a unit, inverse 530.

(1987) divides n-1.

(1987)^2 > n.

n is prime by Pocklington's theorem.