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 A374889 #7 Sep 15 2024 10:55:56
%S A374889 1,6,100,2940,132192,8368360,705938688,76289850000,10252702720000,
%T A374889 1674156061141344,326009771116646400,74554986880418359744,
%U A374889 19767651264345600000000,6010708728599919162000000,2076396132003401567272173568,808279585896351070399895712000
%N A374889 Obverse convolution (n^2)**(2n-1); see Comments.
%C A374889 See A374848 for the definition of obverse convolution and a guide to related sequences.
%F A374889 a(n) ~ 2^(3/2) * n^(2*n + 1/2) / exp(2*n + 2 - Pi*sqrt(2*n)). - _Vaclav Kotesovec_, Sep 15 2024
%t A374889 s[n_] := n^2; t[n_] := 2 n + 1;
%t A374889 u[n_] := Product[s[k] + t[n - k], {k, 0, n}]
%t A374889 Table[u[n], {n, 0, 20}]
%Y A374889 Cf. A000290, A005408, A374848.
%K A374889 nonn
%O A374889 0,2
%A A374889 _Clark Kimberling_, Sep 14 2024