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A141110 Number of cycles and fixed points in the permutation (n, n-2, n-4, ..., 1, ..., n-3, n-1). 1
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; text; internal format)
OFFSET

1,4

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

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

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)

CROSSREFS

Cf. A003558.

Sequence in context: A329359 A235682 A324830 * A325758 A280073 A327523

Adjacent sequences:  A141107 A141108 A141109 * A141111 A141112 A141113

KEYWORD

easy,nonn

AUTHOR

Ramasamy Chandramouli, Jun 05 2008

STATUS

approved

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Last modified August 4 02:24 EDT 2021. Contains 346441 sequences. (Running on oeis4.)