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A134374
a(n) = ((2n+1)!)^2.
13
1, 36, 14400, 25401600, 131681894400, 1593350922240000, 38775788043632640000, 1710012252724199424000000, 126513546505547170185216000000, 14797530453474819213543604224000000
OFFSET
0,2
FORMULA
a(n) = A009445(n)^2 = A001044(2n+1). - Wesley Ivan Hurt, May 02 2014
From Amiram Eldar, Nov 16 2020: (Start)
Sum_{n>=0} 1/a(n) = A334378.
Sum_{n>=0} (-1)^n/a(n) = Im(BesselJ(0, 2*exp(3*Pi*i/4))). (End)
MAPLE
A134374:=n->((2*n+1)!)^2; seq(A134374(n), n=0..10); # Wesley Ivan Hurt, May 02 2014
MATHEMATICA
Table[((2n+1)!)^(2), {n, 0, 10}]
PROG
(PARI) a(n) = ((2*n+1)!)^2; \_ Michel Marcus, Nov 16 2020
KEYWORD
nonn,easy
AUTHOR
Artur Jasinski, Oct 22 2007
STATUS
approved