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%I #7 Mar 30 2012 18:59:35
%S 1,0,1,1,0,2,7,0,26,46,0,2861,40303,0,6446047
%N Number of ways of placing n nonattacking torus queens on 2n+1 X 2n+1 board, similar solutions count only once.
%C Two n-queens solutions p and q are considered similar iff there is a factor f, 0 < f < n, satisfying gcd (f,n) = 1, such that for all k from {0, ..., n-1} q (k * f mod n) = p (k) * f mod n or q is a rotation, a reflection or a shift of such a q. In other words, also expansions are allowed which move the queen at (k, p(k)) to (f * k mod n, f * p(k) mod n).
%C The sequence reduces exactly the objects of A053994 and, via that sequence, these of A007705.
%H M. Engelhardt, <a href="http://www.nqueens.de">The N queens problem</a>
%K nonn,nice,more
%O 1,6
%A _Matthias Engelhardt_
%E Updated link that is transferred from people.freenet.de/nQueens to www.nqueens.de _Matthias Engelhardt_, Apr 21 2010