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 A291547 #7 Aug 26 2017 04:36:39
%S A291547 1,9,3375,121550625,753631499840625,1261673443947253805015625,
%T A291547 822952789790387281855874669859609375,
%U A291547 285018362247755338974104595257347347998199462890625,68512882179510153729154120317673085873841328059500855014801025390625
%N A291547 a(n) = ((2*n-1)!!)^n.
%F A291547 a(n) = ((2*n)!/n!)^n / 2^(n^2).
%F A291547 a(n) ~ 2^(n^2 + n/2) * n^(n^2) / exp(n^2 + 1/24).
%t A291547 Table[Product[2*k - 1, {k, 1, n}]^n, {n, 1, 10}]
%t A291547 Table[((2*n - 1)!!)^n, {n, 1, 10}]
%Y A291547 Cf. A001147, A036740, A254866, A291332.
%K A291547 nonn
%O A291547 1,2
%A A291547 _Vaclav Kotesovec_, Aug 26 2017