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

%I #8 Dec 10 2016 22:39:57

%S 1,2,24,720,40320,518400,479001600,87178291200,38817792000,

%T 6402373705728000,221172909834240000,160571532539658240000,

%U 47726800133326110720000,36662860102418694144000000,43555477801673408643072000000,24113896346562823512391680000000

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

%H Clark Kimberling, <a href="/A279236/b279236.txt">Table of n, a(n) for n = 0..1000</a>

%e (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.

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

%t Numerator[t] (* A279235 *)

%t Denominator[t] (* A279236 *)

%Y Cf. A279235.

%K nonn,easy,frac

%O 0,2

%A _Clark Kimberling_, Dec 08 2016