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 A026949 #11 Jun 20 2022 20:08:09
%S A026949 1,12,83,630,3171,21672,97482,639180,2730615,17543196,72932904,
%T A026949 463291920,1895949055,11961944400,48478715240,304543085040,
%U A026949 1226501910315,7682898791700,30811853728475,192632866196694,770315837004637,4809438625979592,19193549752057758,119719958370912900
%N A026949 a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026374.
%Y A026949 Cf. A026374.
%K A026949 nonn
%O A026949 3,2
%A A026949 _Clark Kimberling_
%E A026949 More terms from _Sean A. Irvine_, Oct 17 2019