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Search: id:A054417
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| A054417 |
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Number of connected 3 X n binary matrices with rightmost column [1,0,0]'. |
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+0
5
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| 1, 5, 37, 249, 1657, 11037, 73533, 489905, 3263921, 21745397, 144875541, 965212201, 6430585769, 42842841485, 285434194093, 1901663763041, 12669557966433, 84409085446373, 562363243040517, 3746663234776665
(list; graph; listen)
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OFFSET
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1,2
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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. a 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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FORMULA
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a(n)=7a(n-1)-3a(n-2)+5a(n-3).
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CROSSREFS
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Cf. A054418-A054421.
Sequence in context: A088582 A088583 A015548 this_sequence A080507 A108049 A121141
Adjacent sequences: A054414 A054415 A054416 this_sequence A054418 A054419 A054420
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KEYWORD
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nonn
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AUTHOR
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njas, 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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