OFFSET
0,2
COMMENTS
Number of ways of placing n labeled balls into n unlabeled (but 9-colored) boxes.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..514
FORMULA
G.f.: A(x) satisfies 9*(x/(1-x))*A(x/(1-x)) = A(x)-1; nine times the binomial transform equals this sequence shifted one place left.
MAPLE
a:= proc(n) option remember; `if`(n=0, 1,
(1+add(binomial(n-1, k-1)*a(n-k), k=1..n-1))*9)
end:
seq(a(n), n=0..25); # Alois P. Heinz, Sep 25 2017
MATHEMATICA
Table[BellB[n, 9], {n, 0, 30}]
PROG
(PARI) my(x='x+O('x^99)); Vec(serlaplace(exp(9*(exp(x)-1)))) \\ Altug Alkan, Sep 17 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Sep 17 2016
STATUS
approved