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 A026883 #4 Mar 30 2012 18:56:11 %S A026883 1,4,16,66,281,1232,5548,25598,120724,580658,2842222,14129842, %T A026883 71212849,363242996,1872444764,9741516322,51092414488,269881127838, %U A026883 1434527328782,7667466737670,41184478999300,222189902624502,1203447917249894 %N A026883 T(2n,n+1), T given by A026769. %K A026883 nonn %O A026883 1,2 %A A026883 _Clark Kimberling_