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 A026223 #4 Mar 30 2012 18:56:05 %S A026223 1,3,5,8,9,11,14,15,17,20,23,24,26,27,29,32,33,35,38,41,42,44,45,47, %T A026223 50,51,53,56,59,60,62,65,68,69,71,72,74,77,78,80,81,83,86,87,89,92,95, %U A026223 96,98,99,101,104,105,107,110,113,114,116,119 %N A026223 (1/3)*s(n+1), where s = A026222. %K A026223 nonn %O A026223 1,2 %A A026223 _Clark Kimberling_