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A002075
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Number of equivalence classes with primitive period n of base 3 necklaces, where necklaces are equivalent under rotation and permutation of symbols.
(Formerly M1160 N0443)
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6
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1, 1, 2, 4, 8, 22, 52, 140, 366, 992, 2684, 7404, 20440, 56992, 159440, 448540, 1266080, 3587610, 10195276, 29057520, 83018728, 237737984, 682196948, 1961323740, 5648590728, 16294032160, 47071589778, 136171440600
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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REFERENCES
| N. J. Fine, Classes of periodic sequences, Illinois J. Math., 2 (1958), 285-302.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Index entries for sequences related to necklaces
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FORMULA
| Reference gives formula.
Sequence A002076 can be found as foolows: Let F3(n) = this sequence, F3*(n) = function from A002076. Then F3*(n) = Sum_{ d divides n } F3(d).
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CROSSREFS
| Cf. A000013, A000048, A002076.
Sequence in context: A155765 A027385 A158324 * A122623 A124014 A100827
Adjacent sequences: A002072 A002073 A002074 * A002076 A002077 A002078
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KEYWORD
| nonn,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Better description and more terms from Mark Weston (mweston(AT)uvic.ca), Oct 07 2001
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