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Search: id:A056941
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| A056941 |
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Antichains (or order ideals) in the poset 5*m*n or plane partitions with rows <= m, columns <= n and entries <= 5 |
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+0
10
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| 1, 1, 1, 1, 6, 1, 1, 21, 21, 1, 1, 56, 196, 56, 1, 1, 126, 1176, 1176, 126, 1, 1, 252, 5292, 14112, 5292, 252, 1, 1, 462, 19404, 116424, 116424, 19404, 462, 1, 1, 792, 60984, 731808, 1646568, 731808, 60984, 792, 1, 1, 1287, 169884, 3737448, 16818516
(list; table; graph; listen)
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OFFSET
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0,5
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REFERENCES
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Berman and Koehler, Cardinalities of finite distributive lattices, Mitteilungen aus dem Mathematischen Seminar Giessen, 121 (1976), p. 103-124
P. A. MacMahon, Combinatory Analysis, Section 495, 1916.
R. P. Stanley, Theory and application of plane partitions. II. Studies in Appl. Math. 50 (1971), p. 259-279. Thm. 18.1
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LINKS
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P. A. MacMahon, Combinatory analysis.
Index entries for sequences related to posets
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FORMULA
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Product[ C(n+m+k, m+k)/C(n+k, k), {k, 0, 4} ]
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CROSSREFS
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Cf. A000372, A056932, A001263, A056939, A056940.
Antidiagonals sum to A005363 (Hoggatt sequence)
Sequence in context: A146988 A060972 A144066 this_sequence A157638 A142596 A155467
Adjacent sequences: A056938 A056939 A056940 this_sequence A056942 A056943 A056944
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KEYWORD
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nonn,easy,tabl
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AUTHOR
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Mitch Harris (Harris.Mitchell(AT)mgh.harvard.edu)
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