OFFSET
1,3
FORMULA
a(n) = n^n-n^(n-1)-(n-1)^n. E.g.f.: (T^3-T^2+T-x)/(T-T^2), where T=T(x) is Euler's tree function (see A000169).
EXAMPLE
a(2)=1: [1->2,2->2].
MAPLE
CROSSREFS
KEYWORD
nonn
AUTHOR
Len Smiley, Dec 09 2001
STATUS
approved