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 A026872 #4 Mar 30 2012 18:56:11 %S A026872 1,4,16,65,268,1120,4738,20265,87542,381600,1677170,7427098,33118073, %T A026872 148618605,670849720,3044548675,13886260129,63627798355,292789942333, %U A026872 1352614829275,6271530026012,29176789293146,136163014291526,637294991967740 %N A026872 T(2n,n+1), T given by A026758. %K A026872 nonn %O A026872 1,2 %A A026872 _Clark Kimberling_