Overview
The Riesel problem is to find the smallest Riesel number k (odd) such that k•2n-1 is composite for every n ≥ 1.
This page was inspired by two threads of the MersenneForum here and here started by (jasong).
Except a few numbers of the odd k's of the Riesel problem a prime was found (mostly a higher n). But what about k's with only a prime with very low n, say n = 1?
For example: k = 17861 is prime for n = 2 and no other n < 50000. So the even value k = 17861 • 2 • 2 = 71444 has no prime for n < 49998.
Accordingly there comes up a question: Is there any even k for which k • 2n − 1 is never prime?
Data
The table contains all 61 odd k < 254601 which got only small prime(s) for n < 10 and no other for n < 1000.
9 candidates of them got no other prime for n < 50000.
These computations were made by Jens K. Andersen and (jasong) in Oct 2007.
(Table missing.)
Status
Only 2 of these 61 candidates got no higher prime n: k = 175567 and k = 239107 (see the Even Riesel project).
