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A084879
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Number of (k,m,n)-multiantichains of multisets with k=3 and m=2.
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0
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1, 3, 18, 189, 2106, 22113, 220158, 2114829, 19853586, 183662073, 1683014598, 15327998469, 139038783066, 1257874611633, 11360039237838, 102475402586109, 923689049088546, 8321664384098793, 74945758272961878, 674816500839877749
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| By a (k,m,n)-multiantichain of multisets we mean an m-multiantichain of k-bounded multisets on an n-set. The elements of a multiantichain could have the multiplicities greater than 1. A multiset is called k-bounded if every its element has the multiplicity not greater than k-1.
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LINKS
| Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, J. Integer Seqs., Vol. 7, 2004.
Index to sequences with linear recurrences with constant coefficients, signature (18,-99,162).
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FORMULA
| 1/2!*(9^n - 2*6^n+3*3^n).
G.f. ( -1+15*x-63*x^2 ) / ( (6*x-1)*(3*x-1)*(9*x-1) ). - R. J. Mathar, Jul 08 2011
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CROSSREFS
| Cf. A016269, A047707, A051112-A051118, A084869-A084883.
Sequence in context: A108994 A006472 A132853 * A141118 A033030 A178014
Adjacent sequences: A084876 A084877 A084878 * A084880 A084881 A084882
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KEYWORD
| nonn
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AUTHOR
| Goran Kilibarda, Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 10 2003
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