OFFSET
1,2
COMMENTS
Compare e.g.f. to arccosh(x) = log(sqrt(x^2-1) + x).
FORMULA
EXAMPLE
E.g.f.: A(x) = x + 2*x^2/2! + 5*x^3/3! + 24*x^4/4! + 129*x^5/5! + ...
where
exp(A(x)) = 1 + 2*(x/2) + 6*(x/2)^2 + 16*(x/2)^3 + 46*(x/2)^4 + 128*(x/2)^5 + ... + A098617(n)*(x/2)^n + ...
MATHEMATICA
With[{nn=30}, Rest[CoefficientList[Series[-Log[Sqrt[1-x^2]-x], {x, 0, nn}], x] Range[0, nn]!]] (* Harvey P. Dale, Dec 01 2011 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 21 2011
STATUS
approved