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A012881 Expansion of e.g.f.: exp(sech(x)*arcsinh(x))=1+x+1/2!*x^2-3/3!*x^3-15/4!*x^4+5/5!*x^5... 0
1, 1, 1, -3, -15, 5, 345, 889, -11263, -82167, 455025, 7869301, -16466703, -906141171, -746021367, 128450716913, 480286325633, -22562588189167, -150637957014303, 4955964959446253, 46203820378253425 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..20.

MATHEMATICA

With[{nn=20}, CoefficientList[Series[Exp[Sech[x]ArcSinh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jul 08 2020 *)

CROSSREFS

Sequence in context: A212203 A286783 A351697 * A248031 A066832 A102777

Adjacent sequences:  A012878 A012879 A012880 * A012882 A012883 A012884

KEYWORD

sign

AUTHOR

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

EXTENSIONS

Definition clarified by Harvey P. Dale, Jul 08 2020

STATUS

approved

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Last modified May 25 19:19 EDT 2022. Contains 354071 sequences. (Running on oeis4.)