Thread: Proth and Riesel Primes View Single Post
2018-01-15, 22:15   #2
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT)

5,693 Posts

Quote:
 Originally Posted by lukerichards I may be missing something here, but why in the definition of Proth ($k\cdot2^n + 1$) and Reisel ($k\cdot2^n - 1$) is there the requirement that $k < 2^n$? There are primes which exist when $k > 2^n$ so is it for the purposes of more efficient primality testing?
Otherwise all odd primes would fit both definitions.
The tests that we use to prove them prime rely on these conditions.