Primality proof for n = 4003:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=29.html>29 is prime.</a>
<br>b^((n-1)/29)-1 mod n = 3778, which is a unit, inverse 1192.
<p><a href=23.html>23 is prime.</a>
<br>b^((n-1)/23)-1 mod n = 3064, which is a unit, inverse 1961.
<p>(23 * 29) divides n-1.
<p>(23 * 29)^2 > n.
<p>n is prime by Pocklington's theorem.