Primality proof for n = 2857:
<p>Take b = 5.
<p>b^(n-1) mod n = 1.
<p><a href=17.html>17 is prime.</a>
<br>b^((n-1)/17)-1 mod n = 1740, which is a unit, inverse 1949.
<p><a href=3.html>3 is prime.</a>
<br>b^((n-1)/3)-1 mod n = 2505, which is a unit, inverse 2021.
<p><a href=2.html>2 is prime.</a>
<br>b^((n-1)/2)-1 mod n = 2855, which is a unit, inverse 1428.
<p>(2^3 * 3 * 17) divides n-1.
<p>(2^3 * 3 * 17)^2 > n.
<p>n is prime by Pocklington's theorem.