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Search: id:A054963
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| A054963 |
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Number of cells in the first column of all directed column-convex polyominoes of area n+1. |
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+0
1
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| 1, 3, 9, 26, 72, 194, 515, 1357, 3563, 9340, 24466, 64068, 167749, 439191, 1149837, 3010334, 7881180, 20633222, 54018503, 141422305, 370248431, 969323008, 2537720614, 6643838856, 17393795977, 45537549099, 119218851345
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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E. Barcucci, R. Pinzani and R. Sprugnoli, Directed column-convex polyominoes by recurrence relations, Lecture Notes in Computer Science, No. 668, Springer, Berlin, 1993, pp. 282-298.
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FORMULA
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a_n = fibonacci(2n)+fibonacci(2n+2)-n; generating function = (1-2x+2x^2)/((1-x)^2(1-3x+x^2))
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CROSSREFS
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Sequence in context: A138237 A121286 A072863 this_sequence A118046 A057153 A084787
Adjacent sequences: A054960 A054961 A054962 this_sequence A054964 A054965 A054966
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 16 2001
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