A129554 - OEIS

%I #7 May 26 2013 15:13:59

%S 0,0,0,0,0,0,0,1,6,66,751,9737,131672,1708295

%N 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).

%H R. D. Chatham, <a href="http://people.moreheadstate.edu/fs/d.chatham/n+kqueens.html">The N+k Queens Problem Page</a>.

%H R. D. Chatham, M. Doyle, G. H. Fricke, J. Reitmann, R. D. Skaggs and M. Wolff, <a href="http://people.moreheadstate.edu/fs/d.chatham/QueensSep2.pdf">Independence and Domination Separation in Chessboard Graphs</a>, J. Combin. Math. Combin. Comput. 68 (2009), 3-17.

%e 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.

%Y Cf. A002562, A129553.

%K more,nonn

%O 1,9

%A R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007