OFFSET
10,2
COMMENTS
FORMULA
E.g.f.: ((x*c(x/2)*(1-2*x)^(-1/2))^10)/10!, where c(x) = g.f. for Catalan numbers A000108, a(0) := 0.
E.g.f.: (-1+(1-2*x)^(-1/2))^10/10!.
EXAMPLE
a(11)=165=3*binomial(11,2) increasing ternary 10-forest with n=11 vertices: there are three 10-forests (nine one vertex trees together with any of the three different 2-vertex trees) each with binomial(11,2)= 55 increasing labelings.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang Sep 14 2007
STATUS
approved