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A141110
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Number of cycles and fixed points in the permutation (n, n-2, n-4, ..., 1, ..., n-3, n-1).
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1
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1, 1, 1, 2, 1, 1, 3, 2, 1, 3, 1, 2, 3, 1, 3, 4, 3, 1, 3, 2, 3, 5, 1, 2, 5, 1, 3, 4, 1, 1, 7, 6, 1, 3, 1, 4, 5, 3, 1, 4, 1, 7, 3, 4, 5, 7, 3, 2, 7, 1, 1, 8, 1, 3, 3, 4, 3, 7, 5, 2, 5, 3, 9, 10, 1, 5, 7, 2, 1, 3, 3, 6, 5, 1, 5, 8, 7, 3, 3, 4, 1, 9, 1, 2, 11
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| The above permutation can be generated by taking S_n: (1, 2, ..., n) and reversing the first two, first three and so on till first n, elements in sequence. Interestingly this permutation orbit has length given by: A003558
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LINKS
| T. D. Noe, Table of n, a(n) for n = 1..10000
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EXAMPLE
| a(20) = 2, since (20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19) has two cycles (1, 20, 19, 17, 13, 5, 12, 3, 16, 11) and (2, 18, 15, 9, 4, 14, 7, 8, 6, 10)
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CROSSREFS
| Cf. A003558.
Sequence in context: A165162 A125106 A152538 * A190770 A025831 A184751
Adjacent sequences: A141107 A141108 A141109 * A141111 A141112 A141113
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KEYWORD
| easy,nonn
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AUTHOR
| Ramasamy Chandramouli (thedavinci(AT)gmail.com), Jun 05 2008
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