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URL: https://oeis.org/A174074

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A174074
Number of circular permutations of length n without consecutive triples i,i+2,i+4.
8
1, 1, 1, 2, 6, 22, 109, 657, 4625, 37186, 336336, 3379058, 37328103, 449669577, 5866178493, 82387080624, 1239364493118, 19881771085788, 338797668091565, 6111688544942463, 116354993433563797, 2331395107113471188, 49042688584011866880, 1080639600739277669092, 24891049832682424745839
OFFSET
0,4
COMMENTS
Circular permutations are permutations whose indices are from the ring of integers modulo n.
REFERENCES
Wayne M. Dymacek, Isaac Lambert and Kyle Parsons, Arithmetic Progressions in Permutations, http://math.ku.edu/~ilambert/CN.pdf, 2012.
LINKS
Kyle Parsons, Arithmetic Progressions in Permutations, thesis, 2011. See Table 3, p. 9.
EXAMPLE
Since a(5)=22, there are (5-1)!-22=2 circular permutations with consecutive triples i,i+2,i+4 in all circular permutations of length 5. They are exactly (0,2,4,1,3) and (0,2,4,3,1).
CROSSREFS
Column 1 of A216719.
Sequence in context: A129535 A375131 A216720 * A290279 A014371 A374618
KEYWORD
nonn
AUTHOR
Isaac Lambert, Mar 06 2010
EXTENSIONS
a(10)-a(15) from Donovan Johnson, Sep 24 2010
a(0)-a(2) prepended and terms a(16) onward added by Max Alekseyev, Feb 04 2024
STATUS
approved