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A056300
Number of primitive (period n) n-bead necklace structures using a maximum of four different colored beads.
5
1, 1, 2, 5, 10, 35, 102, 360, 1232, 4427, 15934, 58465, 215250, 799593, 2983204, 11187200, 42109450, 159081482, 602809326, 2290679807, 8726308212, 33318645341, 127479700198, 488672244040, 1876500180280
OFFSET
1,3
COMMENTS
Turning over the necklace is not allowed. Colors may be permuted without changing the necklace 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]
FORMULA
a(n) = Sum_{d|n} mu(d) * A056292(n/d); mu = A008683.
CROSSREFS
KEYWORD
nonn
STATUS
approved