OFFSET
0,3
COMMENTS
Note that for odd n >= 31, a(n) is negative! - Vaclav Kotesovec, Feb 13 2013
Conjecture: For n > 1, a(n) == 1 (mod n). - Mélika Tebni, Aug 22 2021
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..200
FORMULA
E.g.f.: exp((1+x)^(1+x)-1).
a(n) ~ (n-2)! if n is even and a(n) ~ -(n-2)! if n is odd. - Vaclav Kotesovec, Feb 13 2013
a(n) = Sum_{k=1..n} Bell(k)*A008296(n, k) for n >= 1. - Mélika Tebni, Aug 22 2021
MAPLE
egf:= exp((1+x)^(1+x)-1);
a:= n-> n!*coeff(series(egf, x, n+1), x, n):
seq(a(n), n=0..30); # Alois P. Heinz, Feb 03 2013
# second program: uses Lehmer-Comtet A008296.
seq(A211193(n), n=0..15); # Mélika Tebni, Aug 22 2021
MATHEMATICA
Range[0, 22]! CoefficientList[ Series[ Exp[(1 + x)^(1 + x)], {x, 0, 22}], x]/E
PROG
(PARI) x='x+O('x^66); Vec(serlaplace(exp((1+x)^(1+x)-1))) \\ Joerg Arndt, Nov 30 2014
CROSSREFS
KEYWORD
sign
AUTHOR
Robert G. Wilson v, Feb 03 2013
STATUS
approved