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Search: id:A129551
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| A129551 |
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Number of ways to place n+2 queens and 2 pawns on an n X n board so that no two queens attack each other. |
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+0
2
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| 0, 0, 0, 0, 0, 0, 4, 44, 280, 1304, 12452, 105012, 977664, 9239816, 90776620, 897446092
(list; graph; listen)
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OFFSET
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1,7
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LINKS
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R. D. Chatham, The N+k Queens Problem Page.
R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, Independence and Domination Separation in Chessboard Graphs, Journal of Combinatorial Mathematics and Combinatorial Computing, to appear.
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EXAMPLE
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a(4)=0 because when 6 queens are placed on a 4 X 4 board, at least two queens will be adjacent and therefore mutually attacking.
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CROSSREFS
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Cf. A000170, A129552.
Sequence in context: A051223 A077435 A074751 this_sequence A081078 A035014 A030987
Adjacent sequences: A129548 A129549 A129550 this_sequence A129552 A129553 A129554
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KEYWORD
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more,nonn
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AUTHOR
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R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007
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