A334855 E.g.f. A(x) satisfies: A(x) = tanh(x * exp(A(x))).

1, 2, 7, 32, 141, -48, -20509, -572416, -13236455, -290711040, -6196120193, -125279895552, -2200506714587, -21844509804544, 731664799971163, 69257460487553024, 3772508483052129329, 174474102931077464064, 7365599642083503837175, 286164434343334028247040

Offset: 1

Author

Ilya Gutkovskiy, May 13 2020

Keywords

• sign

Crossrefs

Cf. A227463, A227465.

Programs

Mathematica

nmax = 20; CoefficientList[InverseSeries[Series[ArcTanh[x]/Exp[x], {x, 0, nmax}], x], x] Range[0, nmax]! // Rest

Formula

E.g.f.: series reversion of arctanh(x) / exp(x).