A217238 a(n) = n! * Sum_{k=1..n} k!.

0, 1, 6, 54, 792, 18360, 628560, 29801520, 1864114560, 148458925440, 14652778694400, 1754531487878400, 250496910657100800, 42032247882174950400, 8188505926902446745600, 1832839841627736125184000, 467088574163438830546944000

Offset

0,3

Comments

Variant of A143217.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Formula

a(n) = n!*(!(n+1) - 1).

a(n) = A000142(n) * A007489(n).

Mathematica

Table[n!*Sum[i!, {i, n}], {n, 0, 16}]

Prog

(Magma) [0] cat [Factorial(n)*&+[Factorial(k) : k in [1..n]] : n in [1..20]]; // Wesley Ivan Hurt, Jul 03 2020
(SageMath) f=factorial; [f(n)*sum(f(k) for k in (1..n)) for n in (0..40)] # G. C. Greubel, Jul 12 2022

Crossrefs

Cf. A000142, A007489, A061640, A143217, A217239.

Sequence in context: A366232 A138434 A360545 * A171681 A267837 A049037

Adjacent sequences: A217235 A217236 A217237 * A217239 A217240 A217241

Keyword

nonn,easy

Author

Olivier Gérard, Sep 28 2012

Status

approved