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 A026899 #4 Mar 30 2012 18:56:11 %S A026899 1,6,30,144,687,3296,15972,78294,388320,1947910,9875566,50560246, %T A026899 261177401,1360112590,7134802722,37673830960,200106632766, %U A026899 1068539351340,5733226876876,30894846668416,167137498306038,907416216735816 %N A026899 T(2n+1,n+2), T given by A026780. %K A026899 nonn %O A026899 1,2 %A A026899 _Clark Kimberling_