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A032522
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Number of point symmetric solutions to non-attacking queens problem on n X n board.
(Formerly M0330 N0125)
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7
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1, 0, 0, 2, 2, 4, 8, 4, 16, 12, 48, 80, 136, 420, 1240, 3000, 8152, 18104, 44184, 144620, 375664, 1250692, 3581240, 11675080, 34132592, 115718268, 320403024, 1250901440, 3600075088, 14589438024, 43266334696, 181254386312
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OFFSET
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1,4
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REFERENCES
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N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
R. J. Walker, An enumerative technique for a class of combinatorial problems, pp. 91-94 of Proc. Sympos. Applied Math., vol. 10, Amer. Math. Soc., 1960.
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LINKS
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CROSSREFS
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KEYWORD
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nonn,nice,hard
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AUTHOR
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Miklos SZABO (mike(AT)ludens.elte.hu)
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EXTENSIONS
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More terms for n = 33..36 from W. Schubert, Jul 31 2009
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STATUS
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approved
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