A279309 - OEIS

A279309

Denominators of coefficients in expansion of (1 + cos(sqrt x))/(cosh x).

1, 2, 24, 720, 40320, 3628800, 479001600, 87178291200, 20922789888000, 6402373705728000, 2432902008176640000, 1124000727777607680000, 620448401733239439360000, 36662860102418694144000000, 304888344611713860501504000000, 13960676832220582033489920000000

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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