A262032 a(n) = (2^n)! / n!.

1, 2, 12, 6720, 871782912000, 2192756974447446084726816768000000, 176231850258172450143657485187724278892868772464646100276113742187798200320000000000000

Offset

0,2

Links

Table of n, a(n) for n=0..6.

Formula

a(n) = A000722(n) / A000142(n).

Example

For n = 2, a(n) = (2^n)! / n! = (2^2)! / 2! = 12.

Mathematica

Table[(2^n)!/n!, {n, 0, 6}] (* Michael De Vlieger, Sep 09 2015 *)

Prog

(PARI) a(n) = (2^n)! / n!;
vector(10, n, a(n-1))
(Magma) [Factorial(2^n) / Factorial(n): n in [0..7]]; // Vincenzo Librandi, Sep 10 2015

Crossrefs

Cf. A000722, A000142.

Sequence in context: A118542 A007155 A265092 * A074200 A342104 A274223

Adjacent sequences: A262029 A262030 A262031 * A262033 A262034 A262035

Keyword

nonn,easy

Author

Altug Alkan, Sep 08 2015

Status

approved