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 A335096 #13 Sep 25 2020 04:26:27
%S A335096 0,1,34,55511,11575291716,548347875819272649,
%T A335096 8811385079228718926321932614,
%U A335096 66303398534111438173105653188803948359375,308529654991526005900670429792887300937160115962403125000
%N A335096 a(n) = ((2*n+1)!!)^n * (Sum_{k=1..n} 1/(2*k+1)^n).
%F A335096 a(n) ~ 2^(n*(n + 3/2)) * n^(n*(n+1)) / (3^n * exp(n^2 - 11/24)). - _Vaclav Kotesovec_, Sep 25 2020
%t A335096 Table[((2*n + 1)!!)^n * Sum[1/(2*k + 1)^n, {k, 1, n}], {n, 0, 10}] (* _Vaclav Kotesovec_, Sep 25 2020 *)
%o A335096 (PARI) {a(n) = prod(k=1, n, 2*k+1)^n*sum(k=1, n, 1/(2*k+1)^n)}
%Y A335096 Main diagonal of A335095.
%Y A335096 Cf. A291676.
%K A335096 nonn
%O A335096 0,3
%A A335096 _Seiichi Manyama_, Sep 12 2020