A279306 Numerators of coefficients in expansion of (cosh(x))/(1 + cos(sqrt(x))).

1, 1, 13, 377, 2551, 97711, 1686481, 447824017, 2522468131, 22174988051, 7129179751261, 1852107834946547, 34648570480339663, 828888380086508653, 273996480127378324681, 462007733994120695494433, 308514276772559961052721, 38471181499444351991058251

Offset

0,3

Links

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

Example

(1/2) + (1/8)x + (13/48)x^2 + (377/5760)x^3 + ... ; 1/2, 1/8, 13/48, 377/5760, ... = A279306/A279239.

Mathematica

z = 30; t = CoefficientList[Series[Cosh[x]/(1 + Cos[Sqrt[x]]), {x, 0, z}], x];
Numerator[t]   (* A279306 *)
Denominator[t] (* A279239 *)

Crossrefs

Cf. A279239.

Sequence in context: A171656 A320458 A320635 * A134498 A329554 A267433

Adjacent sequences: A279303 A279304 A279305 * A279307 A279308 A279309

Keyword

nonn,easy,frac

Author

Clark Kimberling, Dec 11 2016

Status

approved