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Search: id:A054393
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| A054393 |
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Number of permutations with certain forbidden subsequences. |
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+0
4
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| 1, 1, 2, 5, 14, 42, 132, 428, 1417, 4757, 16119, 54963, 188219, 646460, 2224944, 7668915, 26461005, 91371594, 315689675, 1091166442, 3772747245, 13047503222, 45131078409, 156129312025, 540181837728, 1869097588540, 6467740095295
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OFFSET
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0,3
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REFERENCES
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E. Barcucci et al., From Motzkin to Catalan Permutations, Discr. Math., 217 (2000), 33-49.
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LINKS
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J. W. Layman, The Hankel Transform and Some of its Properties, J. Integer Sequences, 4 (2001), #01.1.5.
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CROSSREFS
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Interpolates between Motzkin numbers (A001006) and Catalan numbers (A000108). Cf. A005773, A054391-A054394.
Sequence in context: A148329 A024175 A152226 this_sequence A036768 A058094 A080938
Adjacent sequences: A054390 A054391 A054392 this_sequence A054394 A054395 A054396
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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), Elisa Pergola (elisa(AT)dsi.unifi.it), May 21 2000
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