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 A026974 #8 Oct 20 2019 18:52:08
%S A026974 1,12,77,450,2154,11592,51060,261720,1106790,5562216,23051943,
%T A026974 114491286,468950860,2313509520,9409147640,46221336720,187136146566,
%U A026974 916762621320,3700703183930,18096198791748,72903667955404,356052268340208,1432473805470840,6990085402419600,28096469154731484
%N A026974 a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026648.
%K A026974 nonn
%O A026974 3,2
%A A026974 _Clark Kimberling_
%E A026974 More terms from _Sean A. Irvine_, Oct 20 2019