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Denominators of coefficients in expansion of 3/(2 + cos(sqrt(x))).
3

%I #6 Dec 10 2016 22:39:17

%S 1,6,72,2160,362880,1209600,1437004800,784604620800,188305108992000,

%T 19207121117184000,1990556188508160000,10116006549998469120000,

%U 25267129482349117440000,10888869450418352160768000000,914665033835141581504512000000

%N Denominators of coefficients in expansion of 3/(2 + cos(sqrt(x))).

%H Clark Kimberling, <a href="/A279234/b279234.txt">Table of n, a(n) for n = 0..1000</a>

%e (1/1) + (1/6)x + (1/72)x^2 + (1/2160)x^3 - (17/362880)x^4 + ... ; 1/1, 1/6, 1/72, 1/2160, -17/362880, ... = A279232/A279234.

%t z = 26; CoefficientList[Series[3/(2 + Cos[Sqrt[x]]), {x, 0, z}], x];

%Y Cf. A279232, A279233.

%K nonn,easy,frac

%O 0,2

%A _Clark Kimberling_, Dec 08 2016