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E.g.f.: -LambertW(-tanh(x)).
2

%I #7 Nov 10 2017 07:37:57

%S 0,1,2,7,48,461,5488,79171,1347328,26396185,585025024,14473813311,

%T 395433660416,11824374817893,384118189803520,13470784014801787,

%U 507233444671848448,20411081546839908401,874130806090067607552,39696948293418345150327

%N E.g.f.: -LambertW(-tanh(x)).

%H G. C. Greubel, <a href="/A277501/b277501.txt">Table of n, a(n) for n = 0..389</a>

%F a(n) ~ sqrt(1-exp(-2)) * 2^(n-1/2) * (log((exp(1)+1)/(exp(1)-1)))^(1/2-n) * exp(1/2-n) * n^(n-1).

%t CoefficientList[Series[-LambertW[-Tanh[x]], {x, 0, 20}], x] * Range[0, 20]!

%o (PARI) x='x+O('x^10); concat([0], Vec(serlaplace(-lambertw(-tanh(x))))) \\ _G. C. Greubel_, Nov 09 2017

%Y Cf. A238085, A277468, A277480, A277500.

%K nonn

%O 0,3

%A _Vaclav Kotesovec_, Oct 18 2016