A279240 Denominators of coefficients in expansion of (2 cos x)/(1 + cos(sqrt(x))).

1, 4, 24, 2880, 40320, 7257600, 479001600, 697426329600, 20922789888000, 261321375744000, 221172909834240000, 4496002911110430720000, 620448401733239439360000, 806582922253211271168000000, 304888344611713860501504000000, 4244045756995056938180935680000000

Offset

0,2

Links

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

Example

(1/1) + (1/4)x - (11/24)x^2 - (343/2880)x^3 + (871/40320)x^4 + ... ; 1/1, 1/4, -11/24, -343/2880, ... = A279238/A279240.

Mathematica

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

Crossrefs

Cf. A279238, A279239.

Sequence in context: A108185 A110972 A065711 * A279110 A077093 A077092

Adjacent sequences: A279237 A279238 A279239 * A279241 A279242 A279243

Keyword

nonn,easy,frac

Author

Clark Kimberling, Dec 08 2016

Status

approved