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A280845
a(n) = 16^n * n * (n!)^4.
1
0, 16, 8192, 15925248, 86973087744, 1087163596800000, 27052109211893760000, 1212439465398129131520000, 90809637490664903729479680000, 10724436568372543800644091248640000, 1906566501044007786781171777536000000000, 491287106495421596910231193510320537600000000
OFFSET
0,2
LINKS
FORMULA
a(n) ~ Pi/4 * A134374(n).
a(n) ~ Pi^2 * 4^(2n + 1) / exp(4n) * n^(4n + 3).
Lim_{n->infinity} a(n) / ((2n+1)!)^2 = Pi/4.
MATHEMATICA
Table[16^n*n*(n!)^4, {n, 0, 12}] (* Wesley Ivan Hurt, Apr 11 2023 *)
PROG
(PARI) a(n) = 16^n * n * (n!)^4;
CROSSREFS
Sequence in context: A079920 A203390 A221085 * A069986 A366361 A265177
KEYWORD
nonn,easy
AUTHOR
Daniel Suteu, Jan 09 2017
STATUS
approved