OFFSET
6,1
REFERENCES
J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 134.
FORMULA
G.f.: A(x) = B(x)^6*(7776-14543*B(x) +11758*B(x)^2 -5126*B(x)^3 +1200*B(x)^4 -120*B(x)^5)/(1-B(x))^11, where B(x) is g.f. for rooted trees with n nodes, cf. A000081.
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Oct 19 2001
STATUS
approved