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A120087 Denominators of expansion of Debye function for n=4: D(4,x). 3
1, 5, 18, 1, 1440, 1, 75600, 1, 3628800, 1, 167650560, 1, 5230697472000, 1, 336259123200, 1, 53353114214400000, 1, 28100018194440192000, 1, 4817145976189747200000, 1, 91657150256046735360000, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

From Wolfdieter Lang, Jul 17 2013 (Start)

The numerators are given in A120086.

See the link under A120080 for D(n,4) as e.g.f. of 4*B(n)/(n+4) = A227573(n)/A227574(n), n>= 0. (End)

LINKS

Table of n, a(n) for n=0..23.

FORMULA

a(n)=denominator(r(n)), with r(n):=[x^n](1 - 2*x/5 + 2*sum((B(2*k)/((k+2)*(2*k)!))*x^(2*k),0,..infinity)), |x|<2*pi. B(2*k):=A000367(k)/A002445(k) (Bernoulli numbers).

a(n)=denominator(4*B(n)/((n+4)*n!), n >= 0, with the Bernoulli numbers B(n) = A027641(n)/A027642(n). From D(4,x) read as o.g.f. _ Wolfdieter Lang, Jul 17 2013

EXAMPLE

Rationals r(n): [1, -2/5, 1/18, 0, -1/1440, 0, 1/75600, 0,

-1/3628800, 0, 1/167650560, 0, -691/5230697472000,...].

CROSSREFS

A120086, A000367/A002445, A027641/A027642.

Sequence in context: A062223 A116911 A097491 * A180135 A260080 A178365

Adjacent sequences:  A120084 A120085 A120086 * A120088 A120089 A120090

KEYWORD

nonn,easy,frac

AUTHOR

Wolfdieter Lang, Jul 20 2006

STATUS

approved

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Last modified October 15 01:40 EDT 2019. Contains 328025 sequences. (Running on oeis4.)