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Search: id:A129552
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| A129552 |
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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 (symmetric solutions count only once). |
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+0
2
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| 0, 0, 0, 0, 0, 0, 1, 6, 37, 164, 1572, 13133, 122279, 1155103, 11347863, 112182378
(list; graph; listen)
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OFFSET
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1,8
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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. A002562, A129551.
Sequence in context: A129651 A097297 A047670 this_sequence A056338 A056328 A156185
Adjacent sequences: A129549 A129550 A129551 this_sequence A129553 A129554 A129555
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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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