

A279236


Denominators of coefficients in expansion of 1/(2  cos(sqrt(x))).


2



1, 2, 24, 720, 40320, 518400, 479001600, 87178291200, 38817792000, 6402373705728000, 221172909834240000, 160571532539658240000, 47726800133326110720000, 36662860102418694144000000, 43555477801673408643072000000, 24113896346562823512391680000000
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OFFSET

0,2


LINKS



EXAMPLE

(1/1)  (1/2)x + (7/24)x^2  (121/720)x^3 + ... ; 1/1, 1/2, 7/24, 1/6480, 121/720, ... = A279235/A279236.


MATHEMATICA

z = 26; t = CoefficientList[Series[1/(2  Cos[Sqrt[x]]), {x, 0, z}], x];


CROSSREFS



KEYWORD

nonn,easy,frac


AUTHOR



STATUS

approved



