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Search: id:A038758
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| A038758 |
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Number of ways of covering a 2n X 2n lattice by 2n^2 dominoes with exactly 4 horizontal (or vertical) dominoes. |
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+0
3
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| 16, 281, 1785, 7175, 22015, 56406, 126966, 259170, 490050, 871255, 1472471, 2385201, 3726905, 5645500, 8324220, 11986836, 16903236, 23395365, 31843525, 42693035, 56461251, 73744946, 95228050, 121689750, 154012950, 193193091
(list; graph; listen)
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OFFSET
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2,1
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REFERENCES
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P. W. Kasteleyn, The statistics of dimers on a lattice, Physica, 27 (1961), 1209-1225.
M. E. Fisher, Statistical mechanics of dimers on a plane lattice, Physical Review, 124 (1961), 1664-1672.
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LINKS
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Index entries for sequences related to dominoes
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FORMULA
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a(n) = 1/24*n*(n-1)*(n+1)*(12*n^3-11*n-10)
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EXAMPLE
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a(3) = 281 because we have 281 ways to cover a 4 X 4 lattice with exactly 4 horizontal dominoes and exactly 14 vertical dominoes.
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CROSSREFS
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Cf. A004003, A002414, A054344.
Sequence in context: A002303 A158610 A004382 this_sequence A027776 A099279 A039746
Adjacent sequences: A038755 A038756 A038757 this_sequence A038759 A038760 A038761
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KEYWORD
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nonn,easy
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AUTHOR
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Yong Kong (ykong(AT)curagen.com), May 06 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 10 2000
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