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 A084713 #7 Mar 17 2015 23:15:47 %S A084713 3,5,7,0,11,13,0,17,19,0,23,952809757913929,0,29,31,0,1091,37,0,41,43, %T A084713 0,47 %N A084713 Smallest prime of the form (2n-1)^k + 2, or 0 if no such number exists. %C A084713 a(3n+1) = 0, a(24) = 47^113 - 2 is a 189-digit number. %e A084713 a(12) = 952809757913927 = 23^11 + 2. %Y A084713 Cf. A084714. %K A084713 nonn %O A084713 1,1 %A A084713 _Amarnath Murthy_, Jun 10 2003 %E A084713 Edited by _Robert G. Wilson v_, Jun 11 2003