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A328038
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Number of primitive (period n) n-bead bracelet structures which are not periodic palindromes using exactly three different colored beads.
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4
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0, 0, 1, 1, 4, 8, 25, 62, 176, 470, 1311, 3620, 10094, 28209, 79236, 223270, 631240, 1790213, 5090995, 14515788, 41484907, 118821599, 341008317, 980487770, 2823961866, 8146372122, 23534556225, 68083326558, 197209108054, 571910949743, 1660395053569, 4825540091342
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OFFSET
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1,5
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COMMENTS
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Permuting the colors of the beads will not change the structure.
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LINKS
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FORMULA
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EXAMPLE
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For n = 3, the 1 bracelet structure has the pattern: ABC.
For n = 4, the 1 bracelet structure has the pattern: AABC.
For n = 5, the 4 bracelet structures have the patterns: AAABC, AABAC, AABBC, ABABC. The pattern ABBAC is excluded because it is a periodic palindrome.
For n = 6, the 8 bracelet structures have the patterns: ABCCCC, ABBCCC, ABBBCB, ABBCBC, ABBCCB, ABCBBC, AABBCC, AABCBC.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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