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 A027318 #8 Oct 27 2019 19:56:15
%S A027318 1,42,420,3786,33648,297940,2633872,23265744,205446960,1814136746,
%T A027318 16021697220,141535810130,1250763720312,11057433981126,97794407702052,
%U A027318 865284559977150,7659315417653664,67827407480624862,600898634852988364,5325658497658529790
%N A027318 a(n) = Sum_{k=0..m-3} T(n,k) * T(n,k+2), where m=n for n=0,1,2,3; m=2n for n >= 4; and T is given by A026082.
%K A027318 nonn
%O A027318 3,2
%A A027318 _Clark Kimberling_
%E A027318 More terms from _Sean A. Irvine_, Oct 27 2019