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Search: id:A056093
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| A056093 |
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Number of 5-element ordered antichain covers of an unlabeled n-element set. |
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+0
4
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| 30, 2176, 54036, 709956, 6290051, 42606671, 237197942, 1135834242, 4823607212, 18563958502, 65783057592, 217240417628
(list; graph; listen)
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OFFSET
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4,1
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REFERENCES
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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.
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LINKS
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K. S. Brown, Dedekind's problem
Eric Weisstein's World of Mathematics, Antichain covers"
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FORMULA
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a(n)=C(n + 30, 30) - 20*C(n + 22, 22) + 60*C(n + 18, 18) + 20*C(n + 16, 16) + 10*C(n + 15, 15) - 110*C(n + 14, 14) - 120*C(n + 13, 13) + 150*C(n + 12, 12) + 120*C(n + 11, 11) - 240*C(n + 10, 10) + 20*C(n + 9, 9) + 240*C(n + 8, 8) + 40*C(n + 7, 7) - 205*C(n + 6, 6) + 60*C(n + 5, 5) - 210*C(n + 4, 4) + 210*C(n + 3, 3) + 50*C(n + 2, 2) - 100*C(n + 1, 1) + 24*C(n, 0).
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CROSSREFS
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Cf. A056048 for 5-antichain (unordered) covers of a labeled n-set, A051113. See also A056074, A056090.
Sequence in context: A112003 A092608 A092617 this_sequence A056070 A054647 A061162
Adjacent sequences: A056090 A056091 A056092 this_sequence A056094 A056095 A056096
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KEYWORD
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nonn
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AUTHOR
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Vladeta Jovovic, Goran Kilibarda, Zoran Maksimovic (vladeta(AT)Eunet.yu), Jul 27 2000
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