

A059079


Number of nelement T_0antichains on a labeled set.


5




OFFSET

0,1


COMMENTS

An antichain on a set is a T_0antichain if for every two distinct points of the set there exists a member of the antichain containing one but not the other point.


REFERENCES

V. Jovovic and G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127138 (translated in Discrete Mathematics and Applications, 9, (1999), no. 6)
V. Jovovic, G. Kilibarda, On enumeration of the class of all monotone Boolean functions, in preparation.


LINKS



EXAMPLE

a(0) = (1/0!)*[1!*e] = 2; a(1) = (1/1!)*[2!*e] = 5; a(2) = (1/2!)*([4!*e]  2*[3!*e] + [2!*e]) = 19; a(3) = (1/3!)*([8!*e]  6*[6!*e] + 6*[5!*e] + 3*[4!*e]  6*[3!*e] + 2*[2!*e]) = 16654, where [n!*e]=floor(n!*exp(1)).


CROSSREFS



KEYWORD

hard,nonn


AUTHOR



STATUS

approved



