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 A179515 #2 Mar 30 2012 17:31:29 %S A179515 1,6,37,305,3231,42757,687255,13115039,291562263,7437080225, %T A179515 214937130141,6964398942275,250747967052627 %N A179515 a(1) = 1, a( n) = prime(a(n-1)) + 4a(n-1). %t A179515 NestList[ Prime@# + 4# &, 1, 12] %Y A179515 Cf. A007097, A074271, A179274, A179511, A179512, A179513, A179514, A179516, A179517, A179518. %K A179515 nonn %O A179515 1,2 %A A179515 _Robert G. Wilson v_, Jul 17 2010