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Search: id:A000506
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| A000506 |
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One half of the number of permutations of [n] such that the differences have 5 runs with the same signs.
(Formerly M5322 N2313)
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+0
3
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| 61, 841, 7311, 51663, 325446, 1910706, 10715506, 58258210, 309958755, 1623847695, 8412276585, 43220104041, 220683627988, 1121561317408, 5679711010548, 28683869195556, 144552802373145, 727271783033445
(list; graph; listen)
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OFFSET
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6,1
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 260.
L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 260, #13
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FORMULA
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16*a(n)/5^n ->1 as n ->infinity . - DELEHAM Philippe (kolotoko(AT)wanadoo.fr), Feb 22 2004
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CROSSREFS
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A diagonal of A008970.
Sequence in context: A086945 A142365 A093473 this_sequence A008358 A138790 A057534
Adjacent sequences: A000503 A000504 A000505 this_sequence A000507 A000508 A000509
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 21 2004
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