A195394 a(n) = (10*n)!

1, 3628800, 2432902008176640000, 265252859812191058636308480000000, 815915283247897734345611269596115894272000000000, 30414093201713378043612608166064768844377641568960512000000000000

Offset

0,2

Links

Table of n, a(n) for n=0..5.

Formula

From Amiram Eldar, Apr 03 2021: (Start)

a(n) = A000142(A008592(n)).

Sum_{n>=0} 1/a(n) = A195070.

Sum_{n>=0} (-1)^n/a(n) = A196498. (End)

Mathematica

a[n_] := (10*n)!; Array[a, 6, 0] (* Amiram Eldar, Apr 03 2021 *)

Prog

(Magma) [Factorial(10*n): n in [0..10]]

Crossrefs

Cf. A000142, A008592, A010050, A100732, A100733, A100734, A195390, A195391, A195392, A195393.

Cf. A195070, A196498.

Sequence in context: A172540 A071552 A181726 * A053501 A229677 A350335

Adjacent sequences: A195391 A195392 A195393 * A195395 A195396 A195397

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 24 2011

Status

approved