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A009138 Expansion of e.g.f.: cosh(log(1+x)/cosh(x)). 1
1, 0, 1, -3, 0, 0, 210, -1260, 3752, -46872, 690960, -6013920, 58389672, -895065600, 12888358392, -168411308520, 2621915506688, -47022586623488, 824126273574336, -14767693271763840, 293589445235224960 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

FORMULA

a(n) ~ (-1)^n * n! / (2 * Gamma(1/cosh(1)) * n^(1 - 1/cosh(1))). - Vaclav Kotesovec, Jul 31 2018

MAPLE

seq(coeff(series(factorial(n)*cosh(log(1+x)/cosh(x)), x, n+1), x, n), n=0..20); # Muniru A Asiru, Jul 31 2018

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Cosh[Log[1+x]/Cosh[x]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Jun 05 2012 *)

PROG

(PARI) x='x+O('x^30); Vec(serlaplace(cosh(log(1+x)/cosh(x)))) \\ G. C. Greubel, Jul 30 2018

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

CROSSREFS

Sequence in context: A215516 A009133 A180515 * A175562 A319330 A291204

Adjacent sequences:  A009135 A009136 A009137 * A009139 A009140 A009141

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified by Harvey P. Dale, Jun 05 2012

STATUS

approved

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Last modified May 25 14:51 EDT 2022. Contains 354071 sequences. (Running on oeis4.)