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Search: id:A086854
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| A086854 |
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Number of permutations of length n with exactly 3 rising or falling successions. |
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6
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| 0, 0, 0, 0, 2, 16, 120, 888, 7198, 64968, 650644, 7165200, 86059242, 1119549472, 15682257872, 235336043976, 3766695159030, 64052134910168, 1153211148654348, 21915344800505888, 438380075974889154, 9207290871553008240, 202585136417883766472, 4659950328485470292632
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OFFSET
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0,5
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COMMENT
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Permutations of 12...n such that exactly 3 of the following occur: 12, 23, ..., (n-1)n, 21, 32, ..., n(n-1).
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REFERENCES
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F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 263.
J. Riordan, A recurrence for permutations without rising or falling successions. Ann. Math. Statist. 36 (1965), 708-710.
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FORMULA
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Coefficient of t^3 in S[n](t) defined in A002464.
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CROSSREFS
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Cf. A002464, A000130, A000349, A001267, A086852, A086853. A diagonal of A001100.
Sequence in context: A136782 A112710 A046105 this_sequence A026129 A026158 A025185
Adjacent sequences: A086851 A086852 A086853 this_sequence A086855 A086856 A086857
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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), Aug 19 2003
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