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 A169770 Number of open knight's tour diagrams of a 3 X n chessboard that have "type X": both endpoints occur in the same column. 9
 4, 0, 0, 0, 80, 40, 368, 352, 5296, 3744, 48656, 40208, 523808, 415488, 5270976, 4333504, 54215264, 44497728, 551297184, 458337984, 5613555008, 4691821600, 56981627840, 47988689152, 577641089664, 489273948160, 5845628996352 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,1 REFERENCES D. E. Knuth, Long and skinny knight's tours, in Selected Papers on Fun and Games, to appear, 2010. LINKS 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). FORMULA Asymptotic value 0.000169*n*3.11949^n when n is even, 0.0000526*n*3.11949^n when n is odd. CROSSREFS Cf. A070030, A169696, A169764-A169777. Sequence in context: A228630 A174647 A258644 * A287633 A222931 A258645 Adjacent sequences:  A169767 A169768 A169769 * A169771 A169772 A169773 KEYWORD nonn AUTHOR N. J. A. Sloane, May 10 2010, based on a communication from Don Knuth, Apr 28 2010 STATUS approved

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Last modified December 13 08:43 EST 2018. Contains 318082 sequences. (Running on oeis4.)