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 A026947 #11 Oct 18 2019 04:03:09
%S A026947 1,6,24,144,541,3258,12275,74280,282003,1713690,6549906,39938616,
%T A026947 153481299,938430990,3622111560,22195961280,85975792075,527816696850,
%U A026947 2050493623760,12607504827600,49098707209695,302275142049870,1179633190545755,7270432009471224,28423658754983701
%N A026947 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026374.
%K A026947 nonn
%O A026947 1,2
%A A026947 _Clark Kimberling_
%E A026947 More terms from _Sean A. Irvine_, Oct 17 2019