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%I #7 Apr 11 2023 13:26:34
%S 0,16,8192,15925248,86973087744,1087163596800000,27052109211893760000,
%T 1212439465398129131520000,90809637490664903729479680000,
%U 10724436568372543800644091248640000,1906566501044007786781171777536000000000,491287106495421596910231193510320537600000000
%N a(n) = 16^n * n * (n!)^4.
%H Daniel Suteu, <a href="/A280845/b280845.txt">Table of n, a(n) for n = 0..50</a>
%F a(n) ~ Pi/4 * A134374(n).
%F a(n) ~ Pi^2 * 4^(2n + 1) / exp(4n) * n^(4n + 3).
%F Lim_{n->infinity} a(n) / ((2n+1)!)^2 = Pi/4.
%t Table[16^n*n*(n!)^4, {n, 0, 12}] (* _Wesley Ivan Hurt_, Apr 11 2023 *)
%o (PARI) a(n) = 16^n * n * (n!)^4;
%Y Cf. A134374, A280100.
%K nonn,easy
%O 0,2
%A _Daniel Suteu_, Jan 09 2017
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