Primality proof for n = 16843:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=401.html>401 is prime.</a>
<br>b^((n-1)/401)-1 mod n = 9926, which is a unit, inverse 13658.
<p>(401) divides n-1.
<p>(401)^2 > n.
<p>n is prime by Pocklington's theorem.