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Search: id:A099390
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| A099390 |
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Array T(m,n) by antidiagonals: number of domino tilings of the m X n grid. |
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15
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| 0, 1, 1, 0, 2, 0, 1, 3, 3, 1, 0, 5, 0, 5, 0, 1, 8, 11, 11, 8, 1, 0, 13, 0, 36, 0, 13, 0, 1, 21, 41, 95, 95, 41, 21, 1, 0, 34, 0, 281, 0, 281, 0, 34, 0, 1, 55, 153, 781, 1183, 1183, 781, 153, 55, 1, 0, 89, 0, 2245, 0, 6728, 0, 2245, 0, 89, 0, 1, 144, 571, 6336, 14824, 31529
(list; table; graph; listen)
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OFFSET
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1,5
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LINKS
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F. Ardila and R. P. Stanley, Tilings
F. Faase, Counting Hamilton cycles in product graphs
P. E. John and H. Sachs, On a strange observation in the theory of the dimer problem
Per Hakan Lundow, Enumeration of matchings in polygraphs, 1998.
J. Propp, Dimers and Dominoes
Index entries for sequences related to dominoes
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FORMULA
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If m, n even then T(m, n) = Prod[j=1..m/2, Prod[k=1..n/2, 4cos(j*Pi/(m+1))^2 + 4cos(k*Pi/(n+1))^2 ]].
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EXAMPLE
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0, 1, 0, 1, 0, 1,
1, 2, 3, 5, 8, 13,
0, 3, 0, 11, 0, 41,
1, 5,11, 36, 95, 281,
0, 8, 0, 95, 0,1183,
1,13,41,281,1183,6728,
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CROSSREFS
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See also A004003 for more literature on the dimer problem.
Rows 2-12 (without zeros) are A000045, A001835, A005178, A003775, A028468, A028469, A028470, A028471, A028472, A028473, A028474.
Main diagonal is A004003.
Cf. A103997, A103999.
Adjacent sequences: A099387 A099388 A099389 this_sequence A099391 A099392 A099393
Sequence in context: A089112 A103438 A068920 this_sequence A124031 A049600 A004542
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KEYWORD
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tabl,nonn
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AUTHOR
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Ralf Stephan, Oct 16 2004
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