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 A047101 #5 Mar 30 2012 18:56:53
%S A047101 1,2,3,5,10,20,37,70,140,280,544,1065,2130,4260,8418,16684,33368,
%T A047101 66736,132760,264436,528872,1057744,2110233,4212350,8424700,16849400,
%U A047101 33658512,67254158,134508316,269016632,537715716,1074932056,2149864112
%N A047101 Sum{T(i,n-i): i=0,1,...,n}, array T as in A047100.
%K A047101 nonn
%O A047101 0,2
%A A047101 _Clark Kimberling_