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Search: id:A137279
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| A137279 |
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Number of ways of placing (m+1)/2 nonattacking queens on an n X n Mobius chessboard. |
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+0
1
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| 1, 4, 0, 16, 40, 192, 560, 3328, 11772, 63840, 259336, 1550976, 7169656, 42410256, 234044160, 1366190592
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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The chessboard is an n X n standard chessboard whose left and right edges are twisted connected.
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REFERENCES
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J. Bell and B. Stevens, Results for the n-queens problem on the Mobius board, to appear in the Australasian Journal of Combinatorics, 2008.
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EXAMPLE
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a(4)=16 because any queen attacks all but two other squares and every solution is counted twice by enumerating all such placements.
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CROSSREFS
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Cf. A000170, A007705, A002562, A053994, A061989, A061990.
Sequence in context: A007216 A057378 A002979 this_sequence A167350 A156457 A085618
Adjacent sequences: A137276 A137277 A137278 this_sequence A137280 A137281 A137282
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KEYWORD
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nonn
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AUTHOR
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brett stevens (brett(AT)math.carleton.ca), Mar 13 2008
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