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Search: id:A000900
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| A000900 |
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Number of solutions to the rook problem on an n X n board having a certain symmetry group (see Robinson for details).
(Formerly M1964 N0777)
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+0
4
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| 0, 0, 0, 1, 2, 10, 28, 106, 344, 1272, 4592, 17692, 69384, 283560, 1191984, 5171512, 23087168, 105883456, 498572416, 2404766224, 11878871456, 59975885856, 309439708352, 1628919330208, 8746079933568, 47840206525056
(list; graph; listen)
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OFFSET
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0,5
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
L. C. Larson, The number of essentially different nonattacking rook arrangements, J. Recreat. Math., 7 (No. 3, 1974), circa pages 180-181.
R. W. Robinson, Counting arrangements of bishops, pp. 198-214 of Combinatorial Mathematics IV (Adelaide 1975), Lect. Notes Math., 560 (1976).
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..200
E. Lucas, Th\'{e}orie des Nombres. Gauthier-Villars, Paris, 1891, Vol. 1, p. 222.
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FORMULA
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a(n)=(A000085(n)-A000898(int(n/2)))/2
For asymptotics see the Robinson paper.
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MAPLE
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For Maple program see A000903.
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CROSSREFS
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Sequence in context: A053594 A006331 A104657 this_sequence A124023 A127921 A106184
Adjacent sequences: A000897 A000898 A000899 this_sequence A000901 A000902 A000903
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KEYWORD
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nonn,easy,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), May 09 2000
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