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Search: id:A051567
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| A051567 |
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Consider problem of placing N queens on an n X n board so that each queen attacks precisely k others. Here k=1 and sequence gives number of different solutions when N is equal to the upper bound 2[2n/3]. |
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14
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OFFSET
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3,2
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COMMENT
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a(n) = 0 if N does not achieve 2[2n/3].
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REFERENCES
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M. Gardner, The Last Recreations, Springer, 1997, p. 282.
M. Gardner, The Colossal Book of Mathematics, 2001, p. 209.
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CROSSREFS
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Cf. A051568-A051571, A051754-A051759, A019654.
The number of solutions when N takes its maximal value is A051757.
Adjacent sequences: A051564 A051565 A051566 this_sequence A051568 A051569 A051570
Sequence in context: A077496 A019106 A051566 this_sequence A085850 A062526 A019947
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KEYWORD
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nonn,nice
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AUTHOR
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njas
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EXTENSIONS
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Description corrected by and one more term from Jud McCranie, Aug 25 2001
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