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 A279238 Numerators of coefficients in expansion of (cos x)/(1 + cos(sqrt(x))). 3

%I #7 Dec 10 2016 22:40:06

%S 1,1,-11,-343,871,54871,-12359,-102902159,-137687549,344971369,

%T 20000206271,-34379966953693,-452834430450401,18163626705916771,

%U 951418549566510481,-381881231033010506527,-4252976361755938012709,-218740547087902859463611

%N Numerators of coefficients in expansion of (cos x)/(1 + cos(sqrt(x))).

%H Clark Kimberling, <a href="/A279238/b279238.txt">Table of n, a(n) for n = 0..1000</a>

%e (1/2) + (1/8)x - (11/48)x^2 - (343/5760)x^3 + ... ; 1/2, 1/3, -11/48, 1/6480, -343/5760, ... = A279238/A279239.

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

%t Numerator[t] (* A279238 *)

%t Denominator[t] (* A279239 *)

%t %/2 (* A279240 *)

%Y Cf. A279239, A279240.

%K sign,easy,frac

%O 0,3

%A _Clark Kimberling_, Dec 08 2016

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Last modified November 30 12:26 EST 2023. Contains 367461 sequences. (Running on oeis4.)