A279236 Denominators of coefficients in expansion of 1/(2 - cos(sqrt(x))).

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

Offset

0,2

Links

Clark Kimberling, Table of n, a(n) for n = 0..1000

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];
Numerator[t]   (* A279235 *)
Denominator[t] (* A279236 *)

Crossrefs

Cf. A279235.

Sequence in context: A137891 A188959 A093459 * A279309 A010050 A186246

Adjacent sequences: A279233 A279234 A279235 * A279237 A279238 A279239

Keyword

nonn,easy,frac

Author

Clark Kimberling, Dec 08 2016

Status

approved