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A056362
Number of primitive (period n) bracelet structures using a maximum of three different colored beads.
5
1, 1, 1, 2, 4, 8, 18, 39, 94, 222, 572, 1463, 3934, 10584, 29211, 80808, 226430, 636320, 1800318, 5107479, 14548360, 41538874, 118927919, 341187047, 980838750, 2824561080, 8147547156, 23536592010, 68087313892, 197216119544, 571924673368, 1660419530055, 4825587979390
OFFSET
0,4
COMMENTS
Turning over will not create a new bracelet. Permuting the colors of the beads will not change the structure.
REFERENCES
M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
LINKS
FORMULA
a(n) = Sum_{d|n} mu(d)*A056353(n/d) for n > 0.
a(n) = Sum_{k=1..3} A276543(n, k) for n > 0. - Andrew Howroyd, Oct 26 2019
CROSSREFS
KEYWORD
nonn
EXTENSIONS
a(0)=1 prepended and terms a(28) and beyond from Andrew Howroyd, Oct 26 2019
STATUS
approved