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A012149 sech(tan(sin(x)))=1-1/2!*x^2+1/4!*x^4+47/6!*x^6-447/8!*x^8... 0
1, -1, 1, 47, -447, -31649, 1241153, 94750991, -10593064063, -734072274241, 217167723689345, 9078987118530031, -9048136095510326335, 132977311200029875999, 677245929952843206843329 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..14.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sech[Tan[Sin[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Sep 16 2016 *)

CROSSREFS

Sequence in context: A142454 A200954 A126300 * A106104 A009086 A034779

Adjacent sequences:  A012146 A012147 A012148 * A012150 A012151 A012152

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified October 15 23:54 EDT 2019. Contains 328038 sequences. (Running on oeis4.)