A009556 Expansion of e.g.f. sin(x)/cos(tanh(x)) (odd powers only).

1, 2, -24, 104, 5824, -385408, 15920256, -160063744, -67251703808, 9821117788160, -551206277726208, -106679023552528384, 37135946330613907456, -2111279822539107794944, -3285803845056084678279168

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..240

Mathematica

With[{nmax = 50}, CoefficientList[Series[Sin[x]/Cos[Tanh[x]], {x, 0, nmax} ], x]*Range[0, nmax - 1]!][[2 ;; ;; 2]] (* G. C. Greubel, Jan 20 2018 *)

Prog

(PARI) x='x+O('x^50); v=Vec(serlaplace(sin(x)/cos(tanh(x))));  vector((#v-1)\2, n, v[2*n-1]) \\ G. C. Greubel, Jan 20 2018

Crossrefs

Sequence in context: A212568 A121199 A009538 * A179824 A034310 A060817

Adjacent sequences: A009553 A009554 A009555 * A009557 A009558 A009559

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved