  A Sierpinski number is an odd positive integer, k, such that no positive
integer of the form k * 2^n + 1 is prime. Similar to a Sierpinski number, a
Riesel number is an odd positive integer, k, such that no positive integer of
the form k * 2^n + 1 is prime. A cover for such a k is a finite list of
positive integers such that each integer j of the appropriate form has a
factor, d, in the cover, with 1 < d < j. Given a k and its cover, ACL2 is used
to systematically verify that each integer of the given form has a non-trivial
factor in the cover.
