A056052 Number of 7-antichain covers of a labeled n-set.

490, 1305330, 1076513148, 474700998300, 143480504528862, 33962870686689270, 6808412143396065136, 1214116433267798496480, 198951942958529631990834, 30633642863234275154265690, 4502737302793395778228384164

Offset

5,1

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

Table of n, a(n) for n=5..15.

K. S. Brown, Dedekind's problem

Eric Weisstein's World of Mathematics, Antichain covers

Formula

a(n)=(1/7!)*(127^n - 42*95^n + 210*79^n + 140*71^n + 210*67^n - 84*65^n + 14*64^n - 819*63^n - 2520*59^n + 2730*55^n + 840*53^n + 840*51^n - 420*50^n + 2940*49^n + 630*47^n - 5040*45^n + 840*44^n - 1260*43^n + 1680*42^n - 9660*41^n + 1260*40^n + 3360*39^n - 7560*38^n + 11130*37^n + 5880*36^n + 9240*35^n + 2982*34^n - 6300*33^n - 8652*32^n - 9905*31^n - 8400*30^n - 8540*29^n + 13860*28^n + 14490*27^n - 5040*26^n + 10500*25^n + 10080*24^n - 8120*23^n - 15050*22^n - 5040*21^n - 11340*20^n + 20580*19^n + 15750*18^n - 1540*17^n - 5810*16^n - 16485*15^n - 21420*14^n + 26250*13^n + 21000*12^n - 29820*11^n + 3500*10^n + 17640*9^n + 2940*8^n - 16016*7^n + 4410*6^n - 9744*5^n + 9744*4^n + 1764*3^n - 3528*2^n + 720).

Crossrefs

Cf. A051115.

Sequence in context: A287329 A303556 A056936 * A051115 A273809 A060975

Adjacent sequences: A056049 A056050 A056051 * A056053 A056054 A056055

Keyword

nonn

Author

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

Status

approved