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Search: id:A103331
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| A103331 |
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Number of ways to place n+1 queens and a pawn 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, 2, 3, 16, 52, 286, 1403, 8214, 54756, 389833, 2923757, 22932960, 184339572
(list; graph; listen)
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OFFSET
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1,6
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LINKS
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R. D. Chatham, The N+k Queens Problem Page.
R. D. Chatham, G. H. Fricke and R. D. Skaggs, The Queens Separation Problem, Utilitas Mathematica 69 (2006), 129-141.
R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, Indepe ndence 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 since when 5 queens are placed on a 4 X 4 board, at least two of them will be adjacent and therefore mutually attacking.
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CROSSREFS
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Cf. A103330, A002562.
Sequence in context: A012358 A012700 A012705 this_sequence A052506 A052858 A073997
Adjacent sequences: A103328 A103329 A103330 this_sequence A103332 A103333 A103334
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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), Jan 31 2005
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EXTENSIONS
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More terms from R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Feb 15 2005, Apr 20 2007
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