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A279309 Denominators of coefficients in expansion of (1 + cos(sqrt x))/(cosh x). 2
1, 2, 24, 720, 40320, 3628800, 479001600, 87178291200, 20922789888000, 6402373705728000, 2432902008176640000, 1124000727777607680000, 620448401733239439360000, 36662860102418694144000000, 304888344611713860501504000000, 13960676832220582033489920000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Clark Kimberling, Table of n, a(n) for n = 0..1000

EXAMPLE

(2/1) - (1/2)x - (23/24)x^2 + (179/720)x^3 + ... ; 0/1, -1/2, -23/24, 179/720, ... = A279308/A279309.

MATHEMATICA

z = 30; t = CoefficientList[Series[(1 + Cos[Sqrt[x]])/Cosh[x], {x, 0, z}], x];

Numerator[t]   (* A279308 *)

Denominator[t] (* A279309 *)

CROSSREFS

Cf. A279308.

Sequence in context: A188959 A093459 A279236 * A010050 A186246 A012161

Adjacent sequences:  A279306 A279307 A279308 * A279310 A279311 A279312

KEYWORD

nonn,easy,frac

AUTHOR

Clark Kimberling, Dec 11 2016

STATUS

approved

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Last modified August 19 23:59 EDT 2022. Contains 356231 sequences. (Running on oeis4.)