|
%I #11 Nov 17 2015 16:27:26
%S 1,4,0,16,40,192,560,3328,11772,63840,259336,1550976,7169656,42410256,
%T 234044160,1366190592
%N Number of ways of placing ceiling(n/2) nonattacking queens on an n X n Mobius chessboard.
%C The chessboard is an n X n standard chessboard whose left and right edges are twisted connected.
%H J. Bell and B. Stevens, <a href="http://ajc.maths.uq.edu.au/pdf/42/ajc_v42_p021.pdf">Results for the n-queens problem on the Mobius board</a>, Australasian Journal of Combinatorics, vol.42, p.21 (2008).
%e a(4)=16 because any queen attacks all but two other squares and every solution is counted twice by enumerating all such placements.
%Y Cf. A000170, A007705, A002562, A053994, A061989, A061990.
%K nonn,more
%O 1,2
%A Brett Stevens (brett(AT)math.carleton.ca), Mar 13 2008
|
