EXP(-1)*sum(k=>0,k^n/k!) - Benoit Cloitre (abcloitre(AT)wanadoo.fr), May 19 2002 a(n) is asymptotic to n!*(2 Pi r^2 exp(r))^(-1/2) exp(exp (r)-1) / r^n, where r is the positive root of r exp(r) = n. - see e (0)