A279182 - OEIS

%I #6 Dec 10 2016 22:38:58

%S 1,1,12,360,20160,1814400,34214400,3962649600,10461394944000,

%T 457312407552000,1216451004088320000,562000363888803840000,

%U 309914286580039680000,10612933187542253568000000,152444172305856930250752000000,18946632843727932759736320000000

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

%H Clark Kimberling, <a href="/A279182/b279182.txt">Table of n, a(n) for n = 0..1000</a>

%e 1/1 + (1/1)x + (11/12)x^2 + (301/360)x^3 + ... ; 1/1, 1/1, 11/12, 301/360, ... = A279181/A279182.

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

%t Numerator[t]   (* A279181 *)

%t Denominator[t] (* A279182 *)

%Y Cf. A279181.

%K nonn,easy,frac

%O 0,3

%A _Clark Kimberling_, Dec 08 2016