A328038 Number of primitive (period n) n-bead bracelet structures which are not periodic palindromes using exactly three different colored beads.
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
Offset: 1
Keywords
Examples
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.
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..200
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