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A062166
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Number of ways of placing n nonattacking torus queens on 2n+1 X 2n+1 board, similar solutions count only once.
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0
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1, 0, 1, 1, 0, 2, 7, 0, 26, 46, 0, 2861, 40303, 0, 6446047
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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COMMENTS
| 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).
The sequence reduces exactly the objects of A053994 and, via that sequence, these of A007705.
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LINKS
| M. Engelhardt, The N queens problem
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CROSSREFS
| Sequence in context: A016638 A199398 A011294 * A113651 A021373 A199950
Adjacent sequences: A062163 A062164 A062165 * A062167 A062168 A062169
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KEYWORD
| nonn,nice,more,changed
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AUTHOR
| Matthias Engelhardt (Matthias.R.Engelhardt(AT)web.de)
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EXTENSIONS
| Updated link that is transferred from people.freenet.de/nQueens to www.nqueens.de Matthias Engelhardt (Matthias.R.Engelhardt(AT)web.de), Apr 21 2010
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