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 A026973 #8 Oct 20 2019 19:54:15
%S A026973 1,8,52,224,1131,4620,23456,92752,460170,1805760,8946216,34942176,
%T A026973 172593267,673129380,3323413216,12954246368,63944790462,249263001360,
%U A026973 1230668687000,4798770328960,23700302314238,92457112946968,456814709763456,1782991313610720,8813232700137268
%N A026973 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026648.
%K A026973 nonn
%O A026973 2,2
%A A026973 _Clark Kimberling_
%E A026973 More terms from _Sean A. Irvine_, Oct 20 2019