Primality proof for n = 1571:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=157.html>157 is prime.</a>
<br>b^((n-1)/157)-1 mod n = 1023, which is a unit, inverse 43.
<p>(157) divides n-1.
<p>(157)^2 > n.
<p>n is prime by Pocklington's theorem.