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A056341
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Number of bracelets using a maximum of six different colored beads.
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2
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6, 21, 56, 231, 888, 4291, 20646, 107331, 563786, 3037314, 16514106, 90782986, 502474356, 2799220041, 15673673176, 88162676511, 497847963696, 2821127825971, 16035812864946, 91404068329560
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Turning over will not create a new bracelet.
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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
| a(n) = sum phi(d)*6^(n/d)/2/n where d|n and a(n)=6^((n+1)/2)/2 for n odd and a(n)=7/4*6^(n/2) for n even.
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CROSSREFS
| Cf. A000029, A054625.
Sequence in context: A145134 A074745 A056414 * A144899 A053809 A047520
Adjacent sequences: A056338 A056339 A056340 * A056342 A056343 A056344
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KEYWORD
| nonn
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AUTHOR
| Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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