A009831 - OEIS

A009831

Expansion of e.g.f. tanh(x)*exp(tanh(x)).

0, 1, 2, 1, -12, -39, 118, 1233, -536, -50831, -116246, 2696321, 16364252, -173033847, -2126232482, 12037460945, 306170653648, -631883857695, -50385573229614, -72323545938047, 9466502482856388, 51175586766916153

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..21.

FORMULA

E.g.f.: tanh(x)*exp(tanh(x)).

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Tanh[x]*Exp[Tanh[x]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Jul 16 2012 *)

CROSSREFS

Sequence in context: A013157 A062742 A009821 * A012931 A013159 A012590

Adjacent sequences: A009828 A009829 A009830 * A009832 A009833 A009834

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

Definition clarified by Harvey P. Dale, Jul 16 2012

STATUS

approved