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A009090 Expansion of e.g.f. cos(tanh(x))/exp(x). 2
1, -1, 0, 2, 4, -36, -56, 944, 1744, -41104, -86208, 2650592, 6199744, -237023424, -608357504, 28021573376, 77889982720, -4225816615168, -12588540708864, 790713657219584, 2503565961032704, -179579770991391744 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..250

MATHEMATICA

With[{nmax = 30}, CoefficientList[Series[Cos[Tanh[x]]/Exp[x], {x, 0, nmax}], x]*Range[0, nmax]!] (* G. C. Greubel, Jul 25 2018 *)

PROG

(PARI) x='x+O('x^30); Vec(serlaplace(cos(tanh(x))/exp(x))) \\ G. C. Greubel, Jul 25 2018

(MAGMA) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Cos(Tanh(x))/Exp(x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Jul 25 2018

CROSSREFS

Sequence in context: A348094 A140984 A057996 * A009295 A277091 A199495

Adjacent sequences:  A009087 A009088 A009089 * A009091 A009092 A009093

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

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Last modified January 20 09:50 EST 2022. Contains 350471 sequences. (Running on oeis4.)