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A169772
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Number of open knight's tour diagrams of a 3 X n chessboard that have "type B": the endpoints occur in different columns and disagree in color with the cells in the nearest corner
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2
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2, 0, 0, 0, 92, 0, 1064, 0, 14928, 0, 156416, 0, 1785600, 0, 19416704, 0, 211014544, 0, 2261999424, 0, 24067157192, 0, 254242274472, 0, 2669251156032, 0, 27880294589248
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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4,1
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REFERENCES
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D. E. Knuth, Long and skinny knight's tours, in Selected Papers on Fun and Games, to appear, 2010.
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LINKS
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Seiichi Manyama, Table of n, a(n) for n = 4..1000
George Jelliss, Open knight's tours of three-rank boards, Knight's Tour Notes, note 3a (21 October 2000).
George Jelliss, Closed knight's tours of three-rank boards, Knight's Tour Notes, note 3b (21 October 2000).
D. E. Knuth Generating functions for A169770-A169777 and A169696.
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FORMULA
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A169772(n)=0 unless n mod 2 = 0.
Asymptotic value: 0.00144*n*3.11949^n when n is even.
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CROSSREFS
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Cf. A070030, A169696, A169764-A169777.
Sequence in context: A118887 A057383 A218881 * A193542 A193545 A336399
Adjacent sequences: A169769 A169770 A169771 * A169773 A169774 A169775
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, May 10 2010, based on a communication from Don Knuth, Apr 28 2010
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STATUS
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approved
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