OFFSET
2,2
REFERENCES
C. Chauve, S. Dulucq and O. Guibert, Enumeration of some labeled trees, research report RR-1226-99, LaBRI, Bordeaux I University, 1999.
MAPLE
n -> sum((n! / (n-k)!) * (-1)^(n-1-k) * stirling1(n-1, k), k=0..n) - sum(((n-2)! / (n-1-k)!) * (-1)^(n-k) * stirling1(n, k), k=0..n-1);
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Cedric Chauve (chauve(AT)lacim.uqam.ca), May 16 2002
STATUS
approved