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 A048213 #4 Mar 30 2012 18:56:54 %S A048213 2,1,4,6,8,9,12,15,16,20,22,24,25,26,32,33,34,37,38,41,45,47,48,53,56, %T A048213 59,61,62,64,68,69,74,76,77,78,81,84,87,88,89,96,98,100,103,105,106, %U A048213 110,111,114,119,121,127,128,130,131,135,138 %N A048213 a(n)=T(n,1), array T given by A048212. %K A048213 nonn %O A048213 1,1 %A A048213 _Clark Kimberling_