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Search: id:A086855
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| A086855 |
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Number of permutations of length n with exactly 4 rising or falling successions. |
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+0
3
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| 0, 0, 0, 0, 0, 2, 22, 226, 2198, 22120, 236968, 2732268, 33940644, 453148422, 6480322210, 98907371822, 1605581578202, 27631315113916, 502618772515748, 9637245372790760, 194291040277517688, 4109014039030693578, 90968013940830446574, 2104072961763468757082
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OFFSET
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0,6
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COMMENT
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Permutations of 12...n such that exactly 4 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^4 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.
Twice A001268.
Sequence in context: A137109 A002276 A112893 this_sequence A089182 A138140 A151617
Adjacent sequences: A086852 A086853 A086854 this_sequence A086856 A086857 A086858
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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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