OFFSET
0,3
LINKS
Robert Israel, Table of n, a(n) for n = 0..399
FORMULA
a(n) ~ n! / (exp(2 - exp(-1)) * (1 - exp(exp(-1) - 1))^(n+1)). - Vaclav Kotesovec, May 31 2018
a(n) = Sum_{k=0..n} |Stirling1(n,k)| * A007840(k). - Seiichi Manyama, May 11 2023
EXAMPLE
E.g.f.: A(x) = 1 + x + 4*x^2/2! + 25*x^3/3! + 211*x^4/4! + 2238*x^5/5! + 28560*x^6/6! + ...
MAPLE
S:= series(1/(1+log(1+log(1-x))), x, 31):
seq(coeff(S, x, n)*n!, n=0..30); # Robert Israel, May 31 2018
MATHEMATICA
nmax = 20; CoefficientList[Series[1/(1 + Log[1 + Log[1 - x]]), {x, 0, nmax}], x] Range[0, nmax]!
a[0] = 1; a[n_] := a[n] = Sum[Sum[(j - 1)! Abs[StirlingS1[k, j]], {j, 1, k}] a[n - k]/k!, {k, 1, n}]; Table[n! a[n], {n, 0, 20}]
PROG
(PARI) x = 'x + O('x^30); Vec(serlaplace(1/(1 + log(1 + log(1 - x))))) \\ Michel Marcus, May 31 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, May 30 2018
STATUS
approved