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A342161
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Expansion of the exponential generating function (tanh(x) - sech(x) + 1) * exp(x).
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0
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0, 1, 3, 4, -3, -14, 63, 274, -1383, -7934, 50523, 353794, -2702763, -22368254, 199360983, 1903757314, -19391512143, -209865342974, 2404879675443, 29088885112834, -370371188237523, -4951498053124094, 69348874393137903, 1015423886506852354, -15514534163557086903
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = n! [x^n] (tanh(x) - sech(x) + 1) * exp(x).
a(n) = Sum_{i=1..n} binomial(n,i) * (-1)^floor((i-1)/2) * A000111(i).
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MAPLE
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series((2*exp(x)-2)/(exp(-2*x)+1), x, 30):seq(n!*coeff(%, x, n), n=0..24); # Peter Luschny, Mar 05 2021
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PROG
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(PARI) my(x='x+O('x^30)); concat(0, Vec(serlaplace((-1/cosh(x) + tanh(x) + 1)*exp(x)))) \\ Michel Marcus, Mar 05 2021
(SageMath)
def A323834List(prec):
R.<x> = PowerSeriesRing(QQ, default_prec=prec)
f = (2*exp(2*x)*(exp(x) - 1))/(exp(2*x) + 1)
return f.egf_to_ogf().list()
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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