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A056295
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Number of n-bead necklace structures using exactly two different colored beads.
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2
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0, 1, 1, 3, 3, 7, 9, 19, 29, 55, 93, 179, 315, 595, 1095, 2067, 3855, 7315, 13797, 26271, 49939, 95419, 182361, 349715, 671091, 1290871, 2485533, 4794087, 9256395, 17896831, 34636833, 67110931, 130150587, 252648991, 490853415
(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.
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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
| A000013(n)-1.
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MAPLE
| See A000013.
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CROSSREFS
| Cf. A052823.
Sequence in context: A066983 A048240 A122012 * A117525 A075149 A161618
Adjacent sequences: A056292 A056293 A056294 * A056296 A056297 A056298
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KEYWORD
| nonn,easy
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AUTHOR
| Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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