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Search: id:A127686
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| A127686 |
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Number of non-isomorphic maximal independent sets of the n-cycle graph having no symmetry axis. |
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+0
1
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| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 2, 2, 5, 4, 8, 9, 15, 16, 27, 30, 46, 55, 80, 96, 139, 168, 237, 293, 403, 503, 687, 864, 1164, 1477, 1974, 2516, 3348, 4282, 5668, 7284, 9604, 12374, 16279, 21022, 27597, 35718, 46819, 60693, 79480, 103174
(list; graph; listen)
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OFFSET
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1,19
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COMMENT
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Number of non-isomorphic (i.e. defined up to a rotation and a reflection) maximal independent sets of the n-cycle graph having no symmetry axis. Also: Number of cyclic and non-palindromic compositions of n in which each term is either 2 or 3, where a clockwise writing is not distinguished from its counterclockwise counterpart.
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REFERENCES
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R. Bisdorff and J.-L. Marichal, Counting non-isomorphic maximal independent sets of the n-cycle graph, preprint, 2007.
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LINKS
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R. Bisdorff and J.-L. Marichal, Counting non-isomorphic maximal independent sets of the n-cycle graph, preprint, 2007.
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FORMULA
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a(n) = Sum(d divides n) A127683(d) = A127685(n) - A127682(n)
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CROSSREFS
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Cf. A127682, A127683, A127685.
Sequence in context: A008818 A089599 A127683 this_sequence A091434 A034400 A021820
Adjacent sequences: A127683 A127684 A127685 this_sequence A127687 A127688 A127689
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KEYWORD
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easy,nonn
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AUTHOR
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Jean-Luc Marichal (jean-luc.marichal(AT)uni.lu), Jan 24 2007
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