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 A047091 #4 Mar 30 2012 18:56:53 %S A047091 1,1,4,11,41,139,515,1871,7004,26191,99137,376300,1437105,5505203, %T A047091 21167781,81602665,315395985,1221558683,4740410605,18426590090, %U A047091 71736136773,279654633032,1091552835344,4265355947434,16684466516559 %N A047091 T(n,n), array T as in A047089. %K A047091 nonn %O A047091 0,3 %A A047091 _Clark Kimberling_