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A160616 Denominator of Laguerre(n, -2). 3
1, 1, 1, 3, 1, 15, 45, 105, 315, 405, 4725, 155925, 467775, 96525, 42567525, 638512875, 30405375, 10854718875, 97692469875, 618718975875, 189403768125, 194896477400625, 238206805711875, 7044115540336875, 8701554491004375 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Matthew House, Table of n, a(n) for n = 0..506

Eric Weisstein's World of Mathematics, Laguerre Polynomial.

FORMULA

Denominators of coefficients in expansion of exp(2*x/(1 - x))/(1 - x). - Ilya Gutkovskiy, Aug 29 2018

EXAMPLE

1, 3, 7, 43/3, 27, 719/15, 3661/45, 13991/105, 66769/315, 133261/405, 2363513/4725, 116441047/155925, ...

MATHEMATICA

Denominator[Table[LaguerreL[n, -2], {n, 0, 50}]] (* G. C. Greubel, May 06 2018 *)

PROG

(PARI) a(n) = sum(k=0, n, (-1)^k*binomial(n, k)*(-2)^k/k!); \\ Michel Marcus, Aug 10 2015

(MAGMA) [Denominator((&+[Binomial(n, k)*(2^k/Factorial(k)): k in [0..n]])): n in [0..30]]; // G. C. Greubel, May 06 2018

CROSSREFS

For numerators see A160615.

Cf. A087912.

Sequence in context: A053485 A160628 A160604 * A168319 A143565 A143018

Adjacent sequences:  A160613 A160614 A160615 * A160617 A160618 A160619

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Nov 14 2009

STATUS

approved

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Last modified February 16 04:34 EST 2019. Contains 320140 sequences. (Running on oeis4.)