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A053485 Denominators in expansion of exp(2x)/(1-x). 3
1, 1, 1, 3, 1, 15, 45, 21, 315, 2835, 4725, 22275, 93555, 2027025, 42567525, 638512875, 212837625, 2170943775, 13956067125, 618718975875, 9280784638125, 14992036723125, 7522320180375, 49308808782358125, 147926426347074375 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..400

FORMULA

a(n) = denominator( Sum_{k=0..n} 2^k/k! ). - G. C. Greubel, Jan 18 2017

MATHEMATICA

Denominator[Table[Sum[2^k/k!, {k, 0, n}], {n, 0, 50}]] (* G. C. Greubel, Jan 18 2017 *)

PROG

(PARI) for(n=0, 25, print1(denominator(sum(k=0, n, 2^k/k!)), ", ")) \\ G. C. Greubel, Jan 18 2017

CROSSREFS

Cf. A053484, A010842.

Sequence in context: A089278 A213245 A087071 * A160628 A160604 A160616

Adjacent sequences: A053482 A053483 A053484 * A053486 A053487 A053488

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Jan 15 2000

STATUS

approved

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Last modified December 8 07:38 EST 2022. Contains 358691 sequences. (Running on oeis4.)