OFFSET
0,4
FORMULA
E.g.f. 1/cosh(exp(x)-1).
EXAMPLE
sech(exp(x)-1) = 1 - x^2/2! - 3*x^3/3! - 2*x^4/4! + 35*x^5/5! + 233*x^6/6! + ...
MAPLE
a:=series(sech(exp(x)-1), x=0, 25): seq(n!*coeff(a, x, n), n=0..24); # Paolo P. Lava, Mar 27 2019
MATHEMATICA
nmax = 24; CoefficientList[Series[Sech[Exp[x] - 1], {x, 0, nmax}], x] Range[0, nmax]!
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Dec 15 2017
STATUS
approved