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 A191213 #4 Mar 30 2012 18:57:31 %S A191213 1,5,6,15,17,20,22,26,51,53,60,62,68,70,80,82,90,106,141,159,161,186, %T A191213 188,204,206,212,214,240,242,248,250,272,274,282,320,322,330,362,426, %U A191213 465,483,485,546,564,566,618,620,636,638,644,646,726,728,744,746,752,754,816,818 %N A191213 Integers in (-2+A191144)/4; contains A191144 as a proper subsequence. %C A191213 See A191144. %t A191213 (See A191144.) %Y A191213 Cf. A191144, A191113. %K A191213 nonn %O A191213 1,2 %A A191213 _Clark Kimberling_, May 28 2011