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A013241 Expansion of e.g.f. tanh(log(x+1) - tan(x)). 1
0, 0, -1, 0, -6, 8, -90, 448, -2520, 26336, -113400, 1722688, -6419952, 101489984, -67603536, -3543539456, 187400653440, -5000257243648, 101437039896192, -2393471184499712, 47958328313066240, -1096842391672099840, 23404766719036851456 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

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

EXAMPLE

-1/2!*x^2 - 6/4!*x^4 + 8/5!*x^5 - 90/6!*x^6 ...

MATHEMATICA

Range[0, 25]! CoefficientList[Series[Tanh[Log[x + 1] - Tan[x]], {x, 0, 25}], x] (* Vincenzo Librandi, Aug 02 2018 *)

PROG

(MAGMA) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1+Tanh(Log(x+1) - Tan(x)))); [0] cat [Factorial(n-1)*b[n]: n in [2..m]]; // Vincenzo Librandi, Aug 02 2018

(PARI) x = 'x + O('x^30); concat([0, 0], Vec(serlaplace(tanh(log(x+1) - tan(x))))) \\ Michel Marcus, Aug 02 2018

CROSSREFS

Sequence in context: A242490 A216796 A137127 * A013237 A013234 A013240

Adjacent sequences:  A013238 A013239 A013240 * A013242 A013243 A013244

KEYWORD

sign

AUTHOR

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

EXTENSIONS

a(0)=a(1)=0 inserted and title improved by Sean A. Irvine, Aug 02 2018

STATUS

approved

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Last modified October 20 20:24 EDT 2019. Contains 328273 sequences. (Running on oeis4.)