%I A103331
%S A103331 0,0,0,0,0,2,3,16,52,286,1403,8214,54756,389833,2923757,22932960,
%T A103331 184339572
%N 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).
%H A103331 R. D. Chatham, <a href="http://people.moreheadstate.edu/fs/d.chatham/
               n+kqueens.html">The N+k Queens Problem Page</a>.
%H A103331 R. D. Chatham, G. H. Fricke and R. D. Skaggs, <a href="http://people.moreheadstate.edu/
               fs/d.chatham/queenssep.pdf">The Queens Separation Problem</a>, Utilitas 
               Mathematica 69 (2006), 129-141.
%H A103331 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">
               Indepe ndence and Domination Separation in Chessboard Graphs</a>, 
               Journal of Combinatorial Mathematics and Combinatorial Computing, 
               to appear.
%e A103331 a(4) = 0 since when 5 queens are placed on a 4 X 4 board, at least two 
               of them will be adjacent and therefore mutually attacking.
%Y A103331 Cf. A103330, A002562.
%Y A103331 Sequence in context: A012358 A012700 A012705 this_sequence A052506 A052858 
               A073997
%Y A103331 Adjacent sequences: A103328 A103329 A103330 this_sequence A103332 A103333 
               A103334
%K A103331 more,nonn
%O A103331 1,6
%A A103331 R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), Jan 31 2005
%E A103331 More terms from R. Douglas Chatham (d.chatham(AT)moreheadstate.edu), 
               Feb 15 2005, Apr 20 2007