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 A369343 #15 Jan 22 2024 09:24:31
%S A369343 1,1,1,1,3,9,21,49,117,295,761,1993,5261,14025,37699,102151,278587,
%T A369343 764145,2106433,5832863,16217191,45255167,126708863,355848715,
%U A369343 1002145705,2829479797,8007670701,22711890561,64547494347,183790615881,524239904367,1497786769295
%N A369343 a(n) is the constant term in expansion of Product_{k=1..n} (x^(2*k-1) + 1 + 1/x^(2*k-1)).
%C A369343 All terms are odd.
%H A369343 Alois P. Heinz, <a href="/A369343/b369343.txt">Table of n, a(n) for n = 0..630</a>
%F A369343 a(n) ~ 3^(n+1) / (4*sqrt(Pi)*n^(3/2)). - _Vaclav Kotesovec_, Jan 21 2024
%p A369343 b:= proc(n, i) option remember; `if`(n>i^2, 0, `if`(i=0, 1,
%p A369343 b(n, i-1)+b(n+2*i-1, i-1)+b(abs(n-2*i+1), i-1)))
%p A369343 end:
%p A369343 a:= n-> b(0, n):
%p A369343 seq(a(n), n=0..33); # _Alois P. Heinz_, Jan 21 2024
%t A369343 Table[Coefficient[Product[x^(2 k - 1) + 1 + 1/x^(2 k - 1), {k, 1, n}], x, 0], {n, 0, 30}]
%Y A369343 Cf. A005408, A007576, A156700, A292476.
%K A369343 nonn
%O A369343 0,5
%A A369343 _Ilya Gutkovskiy_, Jan 20 2024