Quote:
Originally Posted by Dr Sardonicus
The question of when 2^n  3 alone might be prime may be of some interest in its own right. It wouldn't surprise me at all if someone had compiled a factor table for n into the hundreds, and a list of pseudoprimes for larger n's.

http://www.primenumbers.net/prptop/s...&action=Search
I was interested in 2PRP being enough for these PRPs. In general 2^n2^k1. Most general aPRP for:
"For integers a>1, s>=0, all r>0, all t>0, odd and irreducible {a^s\times\prod{(a^r1)^t}}1 is aPRP, except for the cases a^2a1 and a2 and a1 and 1."
This includes a^22, for which I have done a cursory check for a < 10^13.