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).
0, 0, 0, 0, 0, 2, 3, 16, 52, 286, 1403, 8214, 54756, 389833, 2923757, 22932960, 184339572
Offset: 1
Examples
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 . .
Links
- 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.
Extensions
More terms from R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Feb 15 2005, Apr 20 2007