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 A369387 #5 Jan 22 2024 10:40:25
%S A369387 1,3,9,43,243,1539,10557,75595,558117,4218077,32466849,253624579,
%T A369387 2005655781,16024596491,129159081787,1048931938309,8574963650419,
%U A369387 70507361919587,582730070295737,4838280518142269,40336851095845719,337541054046113077,2834101218805540871
%N A369387 a(n) is the constant term in expansion of Product_{k=1..n} (x^(2*k-1) + 1 + 1/x^(2*k-1))^2.
%t A369387 Table[Coefficient[Product[(x^(2 k - 1) + 1 + 1/x^(2 k - 1))^2, {k, 1, n}], x, 0], {n, 0, 22}]
%Y A369387 Cf. A047653, A156181, A369343.
%K A369387 nonn
%O A369387 0,2
%A A369387 _Ilya Gutkovskiy_, Jan 22 2024