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A002566
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Number of ways to attack all squares on an n X n chessboard using the smallest possible number of queens with each queen attacking at least one other.
(Formerly M4130 N1713)
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1
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0, 6, 20, 12, 70, 960, 22, 352, 10, 216, 4814
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OFFSET
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1,2
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COMMENTS
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Differs from A002564 and A002568 in that each queen is attacking at least one other queen.
M. A. Sainte-Laguë paper has "a(6)=900?".
In other words, the number of minimum total dominating sets in the n X n queen graph. - Eric W. Weisstein, Apr 19 2018
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REFERENCES
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W. Ahrens, Mathematische Unterhaltungen und Spiele, second edition (1910), Vol. 1, p. 301.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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M. A. Sainte-Laguë, Les Réseaux (ou Graphes), Mémorial des Sciences Mathématiques, Fasc. 18, Gauthier-Villars, Paris, 1923, 64 pages. See p. 49.
M. A. Sainte-Laguë, Les Réseaux (ou Graphes), Mémorial des Sciences Mathématiques, Fasc. 18, Gauthier-Villars, Paris, 1923, 64 pages. See p. 49. [Incomplete annotated scan of title page and pages 18-51]
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CROSSREFS
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Cf. A002565 (number of ways up to isomorphism).
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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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