A009757 Expansion of e.g.f. tan(x)/cos(tan(x)), odd powers only.

1, 5, 101, 4297, 311017, 34201485, 5316286925, 1110355789329, 300067100236625, 101902284312853013, 42484968788050104757, 21335944225303831614809, 12704193401200858575308601, 8850034105543023432746843549, 7130974518135579153768747620893

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..224

Mathematica

With[{nmax = 50}, CoefficientList[Series[Tan[x]/Cos[Tan[x]], {x, 0, nmax}], x]*Range[0, nmax - 1]!][[2 ;; ;; 2]] (* G. C. Greubel, Feb 12 2018 *)

Prog

(PARI) x='x+O('x^50); v=Vec(serlaplace(tan(x)/cos(tan(x)))); vector((#v-1)\2 , n, v[2*n-1]) \\ G. C. Greubel, Feb 12 2018

Crossrefs

Sequence in context: A266452 A354332 A074790 * A119556 A009765 A113073

Adjacent sequences: A009754 A009755 A009756 * A009758 A009759 A009760

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested by Olivier Gérard, Mar 15 1997

Status

approved