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Search: id:A062168
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| A062168 |
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Number of permutations with at most 2 queens on any torus diagonal, solutions similar on the torus count only once. |
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+0
2
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| 1, 0, 0, 1, 2, 3, 3, 19, 31, 328, 650, 14542, 37449, 771570
(list; graph; listen)
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OFFSET
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1,5
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LINKS
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M. Engelhardt, The N queens problem
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CROSSREFS
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Sequence in context: A090522 A114728 A057676 this_sequence A019229 A135353 A084956
Adjacent sequences: A062165 A062166 A062167 this_sequence A062169 A062170 A062171
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KEYWORD
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nonn,more
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AUTHOR
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Matthias Engelhardt (Matthias.R.Engelhardt(AT)web.de)
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EXTENSIONS
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As A062167, also this sequence counts classes of "near n-queens solutions". In this sequence, two permutations 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 if 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 contains the objects of A062165.
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