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A056354
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Number of bracelet structures using a maximum of four different colored beads.
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8
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1, 1, 2, 3, 7, 11, 33, 73, 237, 703, 2433, 8309, 30108, 108991, 403262, 1497070, 5607437, 21076571, 79595990, 301492045, 1145560579, 4363503684, 16660204452, 63741248201, 244339646708, 938255682551, 3608668388957, 13900021844558, 53614340398327, 207062143625711
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OFFSET
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0,3
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COMMENTS
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Turning over will not create a new bracelet. Permuting the colors of the beads will not change the structure.
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REFERENCES
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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]
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LINKS
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FORMULA
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Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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a(0)=1 prepended and terms a(26) and beyond from Andrew Howroyd, Oct 25 2019
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STATUS
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approved
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