Numbers k such that 31*2^k+1 is prime.

Terms

a(0) =8a(1) =60a(2) =68a(3) =140a(4) =216a(5) =416a(6) =1808a(7) =1944a(8) =9096a(9) =76596a(10) =93168a(11) =4673544a(12) =5560820a(13) =8348000