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A056303
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Number of primitive (period n) n-bead necklace structures using exactly two different colored beads.
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4
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0, 1, 1, 2, 3, 5, 9, 16, 28, 51, 93, 170, 315, 585, 1091, 2048, 3855, 7280, 13797, 26214, 49929, 95325, 182361, 349520, 671088, 1290555, 2485504, 4793490, 9256395, 17895679, 34636833
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| Turning over the necklace is not allowed. Colors may be permuted without changing the necklace structure. Identical to A000048 for n>1.
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REFERENCES
| M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.
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FORMULA
| Sum mu(d)*A056295(n/d) where d divides n . Alternatively, A000048(n)-A000007(n-1)..
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CROSSREFS
| Cf. A001037.
Sequence in context: A114834 A143961 A128023 * A000048 A074099 A006788
Adjacent sequences: A056300 A056301 A056302 * A056304 A056305 A056306
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KEYWORD
| nonn
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AUTHOR
| Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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