A279331 Denominators of coefficients in expansion of (cos(sqrt x))/(1 - x - x^2).

1, 2, 24, 720, 8064, 3628800, 479001600, 87178291200, 20922789888000, 98498057011200, 187146308321280000, 66117689869271040000, 36496964807837614080000, 403291461126605635584000000, 60977668922342772100300800000, 13960676832220582033489920000000

Offset

0,2

Links

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

Example

(1/1) + (1/2)*x + (37/24)*x^2 + (1469/720)*x^3 + ... , therefore: 1/1, 1/2, 37/24, 1469/720, ... = A279330/A279331.

Mathematica

z = 30; t = CoefficientList[Series[Cos[Sqrt[x]]/(1 - x - x^2), {x, 0, z}], x];
Numerator[t]   (* A279330 *)
Denominator[t] (* A279331 *)

Crossrefs

Cf. A279330.

Sequence in context: A323491 A046977 A309205 * A354378 A119699 A188959

Adjacent sequences: A279328 A279329 A279330 * A279332 A279333 A279334

Keyword

nonn,frac,easy

Author

Clark Kimberling, Dec 12 2016

Status

approved