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A279404
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Independent domination number for queens' graph on an n X n toroidal board.
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4
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1, 1, 1, 2, 5, 4, 5, 4, 5, 5, 5, 6, 7, 7, 5, 8
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OFFSET
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1,4
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COMMENTS
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That is, the minimal number of queens needed to cover an n X n toroidal chessboard so that every square either has a queen on it or is under attack by a queen, but not both.
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LINKS
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FORMULA
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a(3*n) = n if n = 1, 5, 7, 11 (mod 12).
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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STATUS
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approved
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