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A229803
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Domination number for rook graph HR(n) on a triangular board of hexagonal cells. The rook can move along any row of adjacent cells, in any of the three directions.
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1
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1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 9, 10, 10, 11, 11
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listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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The value for HR(20) was obtained by Rob Pratt, Sep 29 2013, using integer-linear programming.
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REFERENCES
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J. Konhauser, D. Velleman, S. Wagon, Which Way Did the Bicycle Go? Washington, DC, Math. Assoc. of America, 1996, pp. 169-172
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LINKS
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EXAMPLE
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For HR(7), the graph can be dominated by the three vertices 6, 11, 26, where we count down from the top.
This graph was called the Queen graph in the DeMaio and Tran paper, but the moves are those of a rook in the classic hexagonal chess game.
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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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EXTENSIONS
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STATUS
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approved
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