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A013335 Expansion of e.g.f. tanh(exp(x) - sec(x)). 1
0, 1, 0, -1, -4, -3, 60, 107, -264, -11175, -40200, 142903, 2392436, 8175637, -327277132, -3256146845, -19824913424, 184016913969, 1628105059824, -33266797736465, -1067099983418644, -14633634217342547, -39212918007355092, 458935991667836379 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

EXAMPLE

x - 1/3!*x^3 - 4/4!*x^4 - 3/5!*x^5 + 60/6!*x^6 ...

MATHEMATICA

Range[0, 30]! CoefficientList[Series[Tanh[Exp[x] - Sec[x]], {x, 0, 30}], x] (* Vincenzo Librandi, Aug 06 2018 *)

PROG

(MAGMA)  m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1+Tanh(Exp(x) - Sec(x)))); [0] cat [Factorial(n-1)*b[n]: n in [2..m]]; // Vincenzo Librandi, Aug 06 2018

(PARI) x = 'x + O('x^30); concat(0, Vec(serlaplace(tanh(exp(x) - 1/cos(x))))) \\ Michel Marcus, Aug 06 2018

CROSSREFS

Sequence in context: A249226 A328193 A273878 * A298314 A299389 A220556

Adjacent sequences:  A013332 A013333 A013334 * A013336 A013337 A013338

KEYWORD

sign

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

EXTENSIONS

a(0)=0 inserted and title improved by Sean A. Irvine, Aug 05 2018

STATUS

approved

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Last modified December 1 09:28 EST 2020. Contains 338833 sequences. (Running on oeis4.)