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A000402
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Number of permutations of [n] in which the longest run has length 3.
(Formerly M4239 N1771)
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1
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1, 6, 41, 293, 2309, 19975, 189524, 1960041, 21993884, 266361634, 3465832370, 48245601976, 715756932697, 11277786883706, 188135296650845
(list; graph; refs; listen; history; internal format)
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OFFSET
| 3,2
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REFERENCES
| F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 261, Table 7.4.1.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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EXAMPLE
| a(4)=6 because we have (124)3, (134)2, (234)1, 4(123), 3(124) and 2(134), where the parentheses surround runs of length 3.
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CROSSREFS
| Cf. A008304.
Sequence in context: A196954 A122371 A083067 * A186654 A152107 A143023
Adjacent sequences: A000399 A000400 A000401 * A000403 A000404 A000405
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Better description from Emeric Deutsch (deutsch(AT)duke.poly.edu), May 08 2004
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