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A103331
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).
2
0, 0, 0, 0, 0, 2, 3, 16, 52, 286, 1403, 8214, 54756, 389833, 2923757, 22932960, 184339572
OFFSET
1,6
LINKS
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.
EXAMPLE
For n=6 the a(6)=2 solutions are
. . Q . . . . . Q . . .
Q . P . . Q Q . P . . Q
. . . Q . . . . Q . . .
. Q . . . . . . . . Q .
. . . . Q . . Q . . . .
. . Q . . . . . . Q . .
CROSSREFS
KEYWORD
more,nonn
AUTHOR
R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Jan 31 2005
EXTENSIONS
More terms from R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Feb 15 2005, Apr 20 2007
STATUS
approved