Primality proof for n = 3259:

Take b = 2.

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

181 is prime.
b^((n-1)/181)-1 mod n = 1423, which is a unit, inverse 2462.

(181) divides n-1.

(181)^2 > n.

n is prime by Pocklington's theorem.