

A229803


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.


1



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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OFFSET

1,3


COMMENTS

The value for HR(20) was obtained by Rob Pratt, Sep 29 2013, using integerlinear programming.


REFERENCES

J. Konhauser, D. Velleman, S. Wagon, Which Way Did the Bicycle Go? Washington, DC, Math. Assoc. of America, 1996, pp. 169172


LINKS



EXAMPLE

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.


CROSSREFS



KEYWORD

nonn,hard,more


AUTHOR



EXTENSIONS



STATUS

approved



