A160622 Denominator of Laguerre(n, 1).

1, 1, 2, 3, 8, 15, 144, 420, 5760, 4536, 403200, 1995840, 6220800, 259459200, 1341204480, 46702656000, 1394852659200, 11115232128000, 376610217984000, 96543730483200, 128047474114560000, 1277273554292736000

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..450

Formula

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

Example

1, 0, -1/2, -2/3, -5/8, -7/15, -37/144, -17/420, 887/5760, 1405/4536, 168919/403200, 958271/1995840, ... = A160621/A160622.

Mathematica

Denominator[Table[LaguerreL[n, 1], {n, 0, 50}]] (* G. C. Greubel, May 06 2018 *)

Prog

(PARI) for(n=0, 30, print1(denominator(sum(k=0, n, binomial(n, k)*((-1)^k/k!))), ", ")) \\ G. C. Greubel, May 06 2018
(Magma) [Denominator((&+[Binomial(n, k)*((-1)^k/Factorial(k)): k in [0..n]])): n in [0..30]]; // G. C. Greubel, May 06 2018

Crossrefs

For numerators see A160621.

Cf. A009940.

Sequence in context: A129108 A230284 A264235 * A153699 A182670 A234696

Adjacent sequences: A160619 A160620 A160621 * A160623 A160624 A160625

Keyword

nonn,frac

Author

N. J. A. Sloane, Nov 14 2009

Status

approved