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A129554
Number of ways to place n+3 queens and 3 pawns on an n X n board so that no two queens attack each other (symmetric solutions count only once).
1
0, 0, 0, 0, 0, 0, 0, 1, 6, 66, 751, 9737, 131672, 1708295
OFFSET
1,9
LINKS
R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, Independence and Domination Separation in Chessboard Graphs, J. Combin. Math. Combin. Comput. 68 (2009), 3-17.
EXAMPLE
a(4)=0 because when 7 queens are placed on a 4 X 4 board, at least two queens will be adjacent and therefore mutually attacking.
CROSSREFS
Sequence in context: A373816 A022024 A186666 * A165229 A247740 A253621
KEYWORD
more,nonn
AUTHOR
R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007
STATUS
approved