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Main diagonal of A291656.
3

%I #13 Sep 25 2020 04:36:15

%S 0,1,10,3527,123296356,757031629267449,1263498691933197473321646,

%T 823340843273442113630752833831086703,

%U 285062591046216676379736060856308430344065653125000

%N Main diagonal of A291656.

%H Seiichi Manyama, <a href="/A291676/b291676.txt">Table of n, a(n) for n = 0..27</a>

%F a(n) = ((2n-1)!!)^n * Sum_{i=1..n} 1/(2*i-1)^n.

%F a(n) ~ 2^(n*(2*n + 1)/2) * n^(n^2) / exp(n^2 + 1/24). - _Vaclav Kotesovec_, Sep 25 2020

%t Table[((2*n - 1)!!)^n * Sum[1/(2*k - 1)^n, {k, 1, n}], {n, 0, 10}] (* _Vaclav Kotesovec_, Sep 25 2020 *)

%Y Cf. A291656, A335096.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Aug 29 2017