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A100444 Bisection of A000255. 0
1, 3, 53, 2119, 148329, 16019531, 2467007773, 513137616783, 138547156531409, 47106033220679059, 19690321886243846661, 9923922230666898717143, 5934505493938805432851513, 4154153845757163802996059099 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..13.

FORMULA

a(n) = (2*n + 1)!*hypergeom([-2*n], [-2*n - 1], -1). - Peter Luschny, Nov 02 2018

D-finite with recurrence a(n) +(-4*n^2-2*n+1)*a(n-1) +2*n*(2*n-3)*a(n-2)=0. - R. J. Mathar, Jul 27 2022

MAPLE

a := n -> (2*n+1)!*hypergeom([-2*n], [-2*n-1], -1):

seq(simplify(a(n)), n=0..13); # Peter Luschny, Nov 02 2018

MATHEMATICA

a[n_] := (2n)! SeriesCoefficient[E^-x / (1-x)^2, {x, 0, 2n}];

Table[a[n], {n, 0, 13}] (* Jean-François Alcover, Jun 11 2019 *)

CROSSREFS

Cf. A000255.

Sequence in context: A012742 A012823 A098932 * A300420 A300683 A296678

Adjacent sequences: A100441 A100442 A100443 * A100445 A100446 A100447

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 21 2004

EXTENSIONS

More terms from Hugo Pfoertner, Nov 26 2004

STATUS

approved

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Last modified December 3 09:50 EST 2022. Contains 358517 sequences. (Running on oeis4.)