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Search: id:A054421
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| A054421 |
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Number of disconnected 3 X n binary matrices. |
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+0
5
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| 0, 1, 11, 102, 882, 7295, 58533, 459484, 3547860, 27043405, 204016879, 1526141666, 11336059046, 83703379691, 614911337833, 4497505562616, 32769214114664, 237956784843737, 1722809101653651, 12440161483566494
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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A connected (0,1) matrix is one where you can get from any black square, i.e. 1, to any other by chess king moves.
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REFERENCES
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R. Levy and J. Shapiro, Uniqueness in paint-by-numbers puzzles, preprint, 2000.
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CROSSREFS
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Cf. A054417-A054420. 4*A054421(n) + 2*A054419(n) + A054420(n) = 7^n.
Sequence in context: A001387 A100580 A087744 this_sequence A037700 A037609 A055150
Adjacent sequences: A054418 A054419 A054420 this_sequence A054422 A054423 A054424
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), May 22 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 23 2000
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