This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A095991 #19 Aug 03 2024 07:08:25
%S A095991 2,3,4,6,14,17,18,23,33,43,45,53,60,70,114,141,162,178,387,657,787,
%T A095991 951,1517,1882,1999,2423,2722,3635,3636,3893,5021,5631,7580,7674,8318,
%U A095991 9479,19761
%N A095991 Numbers m such that f(k) * 2^m - 1 is prime, where f(j) = A070826(j) and k is the number of decimal digits of 2^m.
%C A095991 a(1) through a(32) have been proved to be prime with WinPFGW. a(32) has 7901 digits. No more terms up to 7300.
%C A095991 Results were computed using the PrimeFormGW (PFGW) primality-testing program. - _Hugo Pfoertner_, Nov 14 2019
%e A095991 a(5)=14 because 1155 * 2^14 - 1 = 18923519, a prime.
%t A095991 Do[ If[ PrimeQ[ Product[ Prime[i], {i, Floor[ n / Log[2, 10] + 1]}] * 2^(n - 1) - 1], Print[n]], {n, 7300}] (* _Robert G. Wilson v_, Jul 23 2004 *)
%K A095991 more,nonn,base
%O A095991 1,1
%A A095991 _Jason Earls_, Jul 18 2004
%E A095991 Edited by _Robert G. Wilson v_, Jul 23 2004
%E A095991 a(33)-a(37) from _Michael S. Branicky_, Aug 03 2024