A046707 - OEIS

A046707

a(n) = n!*Sum_{k=0..n/2} n^(2k)/(2k)!.

1, 1, 6, 33, 472, 4745, 99216, 1456273, 39669120, 769528593, 25737068800, 622548099041, 24632715009024, 715109889035737, 32630102257170432, 1106618435304908625, 57151019891266256896, 2219208490411286184737, 127876294410780326952960

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OFFSET

0,3

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..200

MATHEMATICA

Join[{1}, Table[(n)! Sum[n^(2 k) / (2 k)!, {k, 0, n/2}], {n, 20}]] (* Vincenzo Librandi, Apr 08 2020 *)

PROG

(PARI) a(n) = {n!*sum(k=0, n\2, n^(2*k)/(2*k)!)} \\ Andrew Howroyd, Mar 07 2020

CROSSREFS

Sequence in context: A358595 A121376 A354890 * A337825 A183466 A112289

Adjacent sequences: A046704 A046705 A046706 * A046708 A046709 A046710

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

Missing a(0)=1 inserted by Andrew Howroyd, Mar 07 2020

STATUS

approved