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 A026881 #4 Mar 30 2012 18:56:11 %S A026881 1,18,199,1756,13624,97434,659549,4294814,27187126,168499288, %T A026881 1027595830,6188801692,36907274904,218380550880,1284054213847, %U A026881 7511758730412,43762192338180,254086749470802,1471134871883972 %N A026881 T(2n,n-4), T given by A026769. %K A026881 nonn %O A026881 4,2 %A A026881 _Clark Kimberling_