OFFSET
0,5
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
KEYWORD
sign
AUTHOR
Peter Luschny, Aug 09 2019
STATUS
approved