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 A027996 #5 Mar 30 2012 18:56:16
%S A027996 6,26,106,424,1684,6667,26352,104069,410806,1621325,6398688,25254823,
%T A027996 99691822,393600358,1554333406,6139498384,24256359424,95857063972,
%U A027996 378903471934,1498090689910,5924490920776,23435015022946,92721024432286
%N A027996 a(n)=Sum{T(n,k)*T(n,k+2)}, 0<=k<=2n-2, T given by A027926.
%K A027996 nonn
%O A027996 2,1
%A A027996 _Clark Kimberling_