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Search: id:A056320
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| A056320 |
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Number of primitive (aperiodic) reversible strings with n beads using exactly four different colors. |
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+0
2
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| 0, 0, 0, 12, 120, 780, 4212, 20412, 93360, 409260, 1749780, 7338000, 30394560, 124700928, 508291692, 2061586800, 8332140720, 33585682920, 135116412660, 542785390680, 2178110585388, 8733343485120
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OFFSET
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1,4
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COMMENT
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A string and its reverse are considered to be equivalent.
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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)*A056311(n/d) where d|n.
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CROSSREFS
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Cf. A056315.
Sequence in context: A093334 A001816 A133386 this_sequence A056311 A009050 A067358
Adjacent sequences: A056317 A056318 A056319 this_sequence A056321 A056322 A056323
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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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