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 A031004 #4 Mar 30 2012 18:56:19 %S A031004 5,18,32,46,60,63,65,67,69,71,73,74,75,88,108,129,150,171,192,197,200, %T A031004 203,206,209,212,213,215,234,255,276,297,318,339,344,347,350,353,356, %U A031004 359,360,362,381,402,423,444,465,486,491,494 %N A031004 Position of n-th 5 in A030998. %K A031004 nonn %O A031004 1,1 %A A031004 _Clark Kimberling_