%I A129551
%S A129551 0,0,0,0,0,0,4,44,280,1304,12452,105012,977664,9239816,90776620,
%T A129551 897446092
%N A129551 Number of ways to place n+2 queens and 2 pawns on an n X n board so that 
               no two queens attack each other.
%H A129551 R. D. Chatham, <a href="http://people.moreheadstate.edu/fs/d.chatham/
               n+kqueens.html">The N+k Queens Problem Page</a>.
%H A129551 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>, 
               Journal of Combinatorial Mathematics and Combinatorial Computing, 
               to appear.
%e A129551 a(4)=0 because when 6 queens are placed on a 4 X 4 board, at least two 
               queens will be adjacent and therefore mutually attacking.
%Y A129551 Cf. A000170, A129552.
%Y A129551 Sequence in context: A051223 A077435 A074751 this_sequence A081078 A035014 
               A030987
%Y A129551 Adjacent sequences: A129548 A129549 A129550 this_sequence A129552 A129553 
               A129554
%K A129551 more,nonn
%O A129551 1,7
%A A129551 R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Apr 20 2007