Primality proof for n = 1657:
<p>Take b = 3.
<p>b^(n-1) mod n = 1.
<p><a href=23.html>23 is prime.</a>
<br>b^((n-1)/23)-1 mod n = 232, which is a unit, inverse 50.
<p><a href=3.html>3 is prime.</a>
<br>b^((n-1)/3)-1 mod n = 1585, which is a unit, inverse 23.
<p>(3^2 * 23) divides n-1.
<p>(3^2 * 23)^2 > n.
<p>n is prime by Pocklington's theorem.