Primality proof for n = 1723:

Take b = 2.

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

41 is prime.
b^((n-1)/41)-1 mod n = 923, which is a unit, inverse 1695.

7 is prime.
b^((n-1)/7)-1 mod n = 316, which is a unit, inverse 747.

(7 * 41) divides n-1.

(7 * 41)^2 > n.

n is prime by Pocklington's theorem.