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A009559 Expansion of e.g.f. sin(x)/cosh(tan(x)) (odd powers only). 1
1, -4, -4, 104, 5392, 167936, 1592384, -401669248, -50456008448, -2742470413312, 310319594802176, 116183782320392192, 12985923007223566336, -3777809306960427778048, -2961060938622580774715392 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

MATHEMATICA

With[{nmax = 50}, CoefficientList[Series[Sin[x]/Cosh[Tan[x]], {x, 0, nmax}], x]*Range[0, nmax - 1]!][[2 ;; ;; 2]] (* G. C. Greubel, Jan 21 2018 *)

PROG

(PARI) x='x+O('x^50); v=Vec(serlaplace(sin(x)/cosh(tan(x)))); vector((#v-1)\2 , n, v[2*n-1]) \\ G. C. Greubel, Jan 21 2018

CROSSREFS

Sequence in context: A092209 A068337 A009534 * A163196 A219453 A283453

Adjacent sequences:  A009556 A009557 A009558 * A009560 A009561 A009562

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

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Last modified June 27 08:15 EDT 2022. Contains 354891 sequences. (Running on oeis4.)