Primality proof for n = 4013:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=59.html>59 is prime.</a>
<br>b^((n-1)/59)-1 mod n = 3465, which is a unit, inverse 1179.
<p><a href=17.html>17 is prime.</a>
<br>b^((n-1)/17)-1 mod n = 4002, which is a unit, inverse 1824.
<p>(17 * 59) divides n-1.
<p>(17 * 59)^2 > n.
<p>n is prime by Pocklington's theorem.