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A209899
Floor of the expected number of empty cells in a random placement of 2n balls into n cells.
8
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11
OFFSET
1,16
REFERENCES
W. Feller, An Introduction to Probability Theory and its Applications, 2nd ed, Wiley, New York, 1965, p. 226.
FORMULA
a(n) = floor(n*(1-1/n)^(2n)).
MATHEMATICA
Table[Floor[n*(1 - 1/n)^(2 n)], {n, 100}] (* T. D. Noe, Mar 15 2012 *)
CROSSREFS
Cf. A209900.
Sequence in context: A003108 A279223 A214956 * A111898 A279041 A072746
KEYWORD
nonn
AUTHOR
Washington Bomfim, Mar 14 2012
STATUS
approved