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A326719 a(n) = n! * [x^n] (x * tanh(x) * sech(x)) / 2. 1
0, 0, 1, 0, -10, 0, 183, 0, -5540, 0, 252605, 0, -16216590, 0, 1395526867, 0, -155132097160, 0, 21643917078969, 0, -3703711882375250, 0, 762837618324516911, 0, -186174409962685042860, 0, 53131942620810610600693, 0, -17531634979650818116555990, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,5
LINKS
FORMULA
E.g.f.: x*(exp(x) - exp(-x))/(exp(x) + exp(-x))^2.
MAPLE
egf := x*tanh(x)*sech(x)/2: ser := series(egf, x, 30):
seq(n!*coeff(ser, x, n), n=0..29);
CROSSREFS
a(n) = A326722(n, 3) for n >= 0.
Sequence in context: A285477 A089831 A221414 * A070190 A216797 A221305
KEYWORD
sign
AUTHOR
Peter Luschny, Aug 09 2019
STATUS
approved

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Last modified June 1 11:52 EDT 2023. Contains 363068 sequences. (Running on oeis4.)