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A012873 Expansion of e.g.f.: arctan(sech(x)*log(x+1))=x-1/2!*x^2-3/3!*x^3+12/4!*x^4+43/5!*x^5... 0
0, 1, -1, -3, 12, 43, -555, -49, 37632, -154867, -3817845, 45540649, 409535148, -12690409929, -14813266559, 3983011043675, -28691304331680, -1331245986549447, 25689766775914647, 419731311262402229 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..20.

MATHEMATICA

With[{nn=20}, CoefficientList[Series[ArcTan[Sech[x]Log[x+1]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Aug 14 2021 *)

CROSSREFS

Sequence in context: A191112 A066987 A290918 * A282082 A356888 A167477

Adjacent sequences: A012870 A012871 A012872 * A012874 A012875 A012876

KEYWORD

sign

AUTHOR

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

EXTENSIONS

Zero prepended to sequence and definition clarified by Harvey P. Dale, Aug 14 2021

STATUS

approved

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Last modified December 3 17:38 EST 2022. Contains 358535 sequences. (Running on oeis4.)