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 A031313 #4 Mar 30 2012 18:56:23 %S A031313 97,100,103,106,109,247,250,253,256,259,397,400,403,406,409,547,550, %T A031313 553,556,559,697,700,703,706,709,847,850,853,856,859,997 %N A031313 Position of n-th 0 in A031312. %K A031313 nonn %O A031313 1,1 %A A031313 _Clark Kimberling_