A054202 a(n) = (n-1)! * Sum_{k=1..n} floor(k^k/k!).

1, 3, 14, 102, 1032, 12840, 194400, 3457440, 70680960, 1635863040, 42293664000, 1208201702400, 37796100249600, 1285064055475200, 47183768081049600, 1860676781483520000, 78432007085752320000, 3519255355814854656000

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..380

Mathematica

Table[(n-1)!*Sum[Floor[k^k/k!], {k, n}], {n, 20}] (* G. C. Greubel, Jul 31 2019 *)

Prog

(PARI) vector(20, n, (n-1)!*sum(k=1, n, k^k\k!)) \\ G. C. Greubel, Jul 31 2019
(Magma) F:=Factorial; [F(n-1)*(&+[Floor(k^k/F(k)): k in [1..n]]): n in [1..20]]; // G. C. Greubel, Jul 31 2019
(Sage) f=factorial; [f(n-1)*sum(floor(k^k/f(k)) for k in (1..n)) for n in (1..20)] # G. C. Greubel, Jul 31 2019
(GAP) F:=Factorial;; List([1..20], n-> F(n-1)*Sum([1..n], k-> Int(k^k/F(k)) )); # G. C. Greubel, Jul 31 2019

Crossrefs

Cf. A054201.

Sequence in context: A284760 A076015 A004659 * A084420 A163882 A271213

Adjacent sequences: A054199 A054200 A054201 * A054203 A054204 A054205

Keyword

nonn,easy

Author

N. J. A. Sloane, Apr 29 2000

Status

approved