OFFSET
1,4
COMMENTS
The e.g.f. at x/2 seems to admit an integer representation: arccosh(exp(x)-tanh(x)) = 2*x/(2*1!) +4*x^2/(2^2*2!) -6*x^3/(2^3*3!) -56*x^4/(2^4*4!) +90*x^5/(2^5*5!) +2524*x^6/(2^6*6!) ...
CROSSREFS
KEYWORD
sign,frac
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Values replaced by numerators. - R. J. Mathar, Dec 22 2011
STATUS
approved