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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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1
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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| A string and its reverse are considered to be equivalent.
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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
| sum mu(d)*A056311(n/d) where d|n.
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CROSSREFS
| Cf. A056315.
Sequence in context: A093334 A001816 A133386 * A056311 A009050 A067358
Adjacent sequences: A056317 A056318 A056319 * A056321 A056322 A056323
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KEYWORD
| nonn
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AUTHOR
| Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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