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A012419 Expansion of e.g.f.: sech(arctan(x)*exp(x))=1-1/2!*x^2-6/3!*x^3-11/4!*x^4+100/5!*x^5... 0
1, 0, -1, -6, -11, 100, 995, 2030, -45943, -568632, -1189145, 54818082, 845395901, 1936128428, -142744278261, -2685086733290, -6197620433007, 713212265955216, 15393015776009807, 26780979282600266 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..19.

MATHEMATICA

With[{nn=20}, CoefficientList[Series[Sech[ArcTan[x]Exp[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 06 2016 *)

CROSSREFS

Sequence in context: A192893 A188599 A217934 * A012663 A180929 A212592

Adjacent sequences:  A012416 A012417 A012418 * A012420 A012421 A012422

KEYWORD

sign

AUTHOR

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

EXTENSIONS

Definition (Name) clarified by Harvey P. Dale, Mar 06 2016

STATUS

approved

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Last modified February 25 19:39 EST 2021. Contains 341618 sequences. (Running on oeis4.)