OFFSET
0,3
COMMENTS
Binomial transform of aeration of A166356.
FORMULA
E.g.f.: exp(x)*(1+x*arctanh(x)).
a(n) = Sum_{k=0..n} C(n,k)*A166356(k/2)*(1+(-1)^k)/2.
a(n) ~ (exp(1) + (-1)^n*exp(-1)) * (n-1)! / 2. - Vaclav Kotesovec, Aug 17 2018
MATHEMATICA
(* The function RiordanArray is defined in A256893. *)
nmax = 21; R = RiordanArray[1 + # ArcTanh[#]&, #&, nmax + 1, True];
Total /@ R (* Jean-François Alcover, Jul 20 2019 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Oct 12 2009
STATUS
approved