

A127685


Number of nonisomorphic maximal independent sets of the ncycle 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
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OFFSET

1,6


COMMENTS

Number of nonisomorphic (i.e. defined up to a rotation and a reflection) maximal independent sets of the ncycle 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 nonisomorphic maximal independent sets of the ncycle graph, ar2007.


LINKS

Table of n, a(n) for n=1..57.
R. Bisdorff and J.L. Marichal, Counting nonisomorphic maximal independent sets of the ncycle graph, arXiv:0701647 (2007) and JIS 11 (2008) 08.5.7.


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

Cf. A127682, A127683, A001608.
Sequence in context: A053267 A058768 A127682 * A127687 A024156 A241316
Adjacent sequences: A127682 A127683 A127684 * A127686 A127687 A127688


KEYWORD

easy,nonn


AUTHOR

JeanLuc Marichal (jeanluc.marichal(AT)uni.lu), Jan 24 2007


STATUS

approved



