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Search: id:A056281
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| A056281 |
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Number of primitive (aperiodic) word structures of length n which contain exactly five different symbols. |
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+0
1
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| 0, 0, 0, 0, 1, 15, 140, 1050, 6951, 42524, 246730, 1379385, 7508501, 40074895, 210766919, 1096189500, 5652751651, 28958088579, 147589284710, 749206047975, 3791262568261, 19137821665325, 96416888184100
(list; graph; listen)
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OFFSET
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1,6
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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)*A000481(n/d) where d|n and n>0.
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CROSSREFS
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Cf. A056270.
Sequence in context: A133716 A035330 A002803 this_sequence A000481 A055903 A026859
Adjacent sequences: A056278 A056279 A056280 this_sequence A056282 A056283 A056284
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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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