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Search: id:A056274
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| A056274 |
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Number of primitive (aperiodic) word structures of length n using a 3-ary alphabet. |
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+0
2
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| 1, 1, 4, 12, 40, 116, 364, 1080, 3276, 9800, 29524, 88440, 265720, 796796, 2391440, 7173360, 21523360, 64566684, 193710244, 581120880, 1743391832, 5230147076, 15690529804, 47071499760, 141214768200
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same 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.
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FORMULA
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Sum mu(d)*A007051(n/d-1) where d|n and n>0.
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CROSSREFS
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Cf. A054718.
Sequence in context: A149330 A149331 A009532 this_sequence A058353 A104525 A126986
Adjacent sequences: A056271 A056272 A056273 this_sequence A056275 A056276 A056277
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KEYWORD
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nonn
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AUTHOR
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Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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