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 A077314 #10 Jun 09 2018 08:42:20 %S A077314 3,7,13,31,97,127,223,1567,3583,4801,6271,8191,19207,25087,33613, %T A077314 76831,131071,401407,524287,917503,1229311,1605631,3764767,6588343, %U A077314 14680063,184473631,737894527,2147483647,2259801991,2877292543,3758096383 %N A077314 Primes of the form 2^r*7^s - 1. %C A077314 In all terms except 3, r is odd. - _Robert Israel_, Jun 08 2018 %H A077314 Robert Israel, <a href="/A077314/b077314.txt">Table of n, a(n) for n = 1..1736</a> %p A077314 N:= 10^30: # for all terms <= N %p A077314 sort(select(isprime, [3, seq(seq(2^r*7^s-1, r=1..ilog2((N+1)/7^s),2), %p A077314 s=0..floor(log[7]((N+1)/2)))])); # _Robert Israel_, Jun 08 2018 %Y A077314 Cf. A023509, A077313. %K A077314 nonn %O A077314 1,1 %A A077314 _Amarnath Murthy_, Nov 04 2002 %E A077314 Corrected and extended by _Ray Chandler_, Aug 02 2003