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 A030594 #4 Mar 30 2012 18:56:19 %S A030594 3,9,15,21,27,28,30,32,33,42,51,60,69,78,80,83,86,87,96,105,114,123, %T A030594 132,134,137,140,141,150,159,168,177,186,188,191,194,195,204,213,222, %U A030594 231,240,242,245,248,249,250,253,256,258,259,262 %N A030594 Position of n-th 5 in A030588. %K A030594 nonn %O A030594 1,1 %A A030594 _Clark Kimberling_