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A127685
Number of non-isomorphic maximal independent sets of the n-cycle graph.
2
0, 1, 1, 1, 1, 2, 1, 2, 2, 3, 2, 4, 3, 5, 5, 7, 6, 10, 9, 14, 14, 20, 20, 30, 31, 44, 48, 67, 74, 104, 117, 161, 188, 254, 302, 407, 489, 654, 801, 1064, 1315, 1742, 2174, 2867, 3613, 4747, 6019, 7900, 10069, 13190, 16895, 22103, 28413, 37150, 47900, 62590, 80912
OFFSET
1,6
COMMENTS
Number of non-isomorphic (i.e. defined up to a rotation and a reflection) maximal independent sets of the n-cycle graph. Also: Number of cyclic compositions of n in which each term is either 2 or 3, where a clockwise writing is not distinguished from its counterclockwise counterpart.
REFERENCES
R. Bisdorff and J.-L. Marichal, Counting non-isomorphic maximal independent sets of the n-cycle graph, ar2007.
FORMULA
a(n) = A127682(n) + Sum(d divides n) A127683(d) = (1/2)*(A127682(n) + (1/n)*(Sum(d divides n) A000010(n/d) A001608(d)))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jean-Luc Marichal (jean-luc.marichal(AT)uni.lu), Jan 24 2007
STATUS
approved