A326719 a(n) = n! * [x^n] (x * tanh(x) * sech(x)) / 2.

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

Offset

0,5

Links

Table of n, a(n) for n=0..29.

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

Adjacent sequences: A326716 A326717 A326718 * A326720 A326721 A326722

Keyword

sign

Author

Peter Luschny, Aug 09 2019

Status

approved