OFFSET
1,3
LINKS
Math.Stackexchange.Com, Marko R. Riedel et al., Labeled trees with a certain condition
FORMULA
a(n) = (n-2)! Sum_{k=1..n-2} C(n,k) k! [u^k][z^{n-2}] Product_{q=1..n-2} (1 + u z^q/q!).
CROSSREFS
KEYWORD
nonn
AUTHOR
Marko Riedel, Jul 02 2016
STATUS
approved