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 A048220 #4 Mar 30 2012 18:56:54 %S A048220 1,1,2,1,2,1,3,1,1,2,3,1,4,2,1,1,2,3,4,1,5,1,3,1,1,1,4,5,3,6,2,1,1,1, %T A048220 4,3,1,1,5,6,1,7,3,4,1,2,1,1,2,5,3,4,1,6,7,1,8,3,1,5,1,1,4,1,2,6,2,1, %U A048220 1,7,8,5,9,1,3,1,1,1,2,6,1,4,3,1,5,7,1,1,1,8 %N A048220 a(n)=least m such that column m of T contains n, array T given by A048212. %K A048220 nonn %O A048220 1,3 %A A048220 _Clark Kimberling_