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 A026972 #8 Oct 20 2019 18:39:46
%S A026972 1,6,24,108,406,1908,7289,34248,131766,623700,2416836,11487528,
%T A026972 44745468,213451560,834897375,3993910416,15673923910,75152083716,
%U A026972 295737641768,1420670333640,5603322265428,26960309526744,106539505068194,513309625743600,2031786103702780,9800639852315208
%N A026972 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026648.
%K A026972 nonn
%O A026972 1,2
%A A026972 _Clark Kimberling_
%E A026972 More terms from _Sean A. Irvine_, Oct 20 2019