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 A117480 #5 Mar 30 2012 16:50:25 %S A117480 3,5,9,15,39,99,345,22269,79809,187125,347979,2171619,4219797675, %T A117480 98059918335 %N A117480 A093483(n) + 1. %K A117480 nonn %O A117480 1,1 %A A117480 _N. J. A. Sloane_, Apr 19 2007