The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60th year, we have over 367,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The value for HR(20) was obtained by Rob Pratt, Sep 29 2013, using integer-linear programming. REFERENCES J. Konhauser, D. Velleman, S. Wagon, Which Way Did the Bicycle Go? Washington, DC, Math. Assoc. of America, 1996, pp. 169-172 LINKS Table of n, a(n) for n=1..24. William Herbert Bird, Computational methods for domination problems, University of Victoria, 2017. See Table 2.4 on p. 32. J. DeMaio and H. L. Tran, Domination and independence on a triangular honeycomb chessboard, Coll. Math. J. 44 (2013) 307-314. Stan Wagon, Graph Theory Problems from Hexagonal and Traditional Chess, The College Mathematics Journal, Vol. 45, No. 4, September 2014, pp. 278-287 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 Cf. A075458, A075324, A075561, A006075. Sequence in context: A121828 A057357 A308358 * A029123 A025777 A269862 Adjacent sequences: A229800 A229801 A229802 * A229804 A229805 A229806 KEYWORD nonn,hard,more AUTHOR Stan Wagon, Sep 29 2013 EXTENSIONS a(21)-a(24) from Bird added by Andrey Zabolotskiy, Sep 03 2021 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 7 05:18 EST 2023. Contains 367629 sequences. (Running on oeis4.)