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 A131308 #2 Mar 30 2012 18:51:52 %S A131308 0,2,2,2,1,4,4,4,2,6,6,6,3,8,8,8,4,10,10,10,5,12,12,12,6,14,14,14,7, %T A131308 16,16,16,8,18,18,18,9,20,20,20,10,22,22,22,11,24,24,24,12,26,26,26, %U A131308 13,28,28,28,14,30,30,30,15,32,32,32,16,34,34,34,17,36,36,36,18,38,38,38,19 %N A131308 Alternate A001477 and tripled 2*A000027. %K A131308 nonn %O A131308 0,2 %A A131308 _Paul Curtz_, Sep 29 2007