A056049 Number of 6-antichain covers of a labeled n-set.

1, 1375, 751192, 187216960, 29650991279, 3554308158345, 355235190457414, 31360944940860370, 2536696962910365277, 192628889065040142715, 13964833124133659520116, 978098391719401853480580

Offset

4,2

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, 127-138 (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

Vincenzo Librandi, Table of n, a(n) for n = 4..200

K. S. Brown, Dedekind's problem

Eric Weisstein's World of Mathematics, Antichain covers

Formula

a(n)=(1/6!)*(63^n - 30*47^n + 120*39^n + 60*35^n + 60*33^n - 12*32^n - 345*31^n - 720*29^n + 810*27^n + 120*26^n + 480*25^n + 360*24^n - 480*23^n - 720*22^n - 240*21^n - 540*20^n + 1380*19^n + 750*18^n + 60*17^n - 210*16^n - 1535*15^n - 1820*14^n + 2250*13^n + 1800*12^n - 2820*11^n + 300*10^n + 2040*9^n + 340*8^n - 1815*7^n + 510*6^n - 1350*5^n + 1350*4^n + 274*3^n - 548*2^n + 120).

Mathematica

Table[(1 / 6!) (63^n - 30*47^n + 120*39^n + 60*35^n + 60 *33^n - 12*32^n - 345*31^n-720*29^n + 810*27^n + 120*26^n + 480*25^n + 360*24^n - 480*23^n - 720*22^n -240*21^n - 540*20^n + 1380*19^n + 750*18^n + 60*17^n - 210*16^n - 1535*15^n - 1820*14^n + 2250*13^n + 1800*12^n - 2820*11^n + 300*10^n + 2040*9^n + 340*8^n - 1815*7^n + 510*6^n - 1350*5^n + 1350*4^n + 274*3^n -548*2^n + 120), {n, 4, 20}] (* Vincenzo Librandi, Jun 17 2013 *)

Crossrefs

Cf. A051114.

Sequence in context: A349235 A045131 A365868 * A206340 A056087 A122692

Adjacent sequences: A056046 A056047 A056048 * A056050 A056051 A056052

Keyword

nonn

Author

Vladeta Jovovic, Goran Kilibarda, Zoran Maksimovic, Jul 25 2000

Status

approved