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Search: id:A096168
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| A096168 |
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Number of abelian cube-free words over a 3-letter alphabet. |
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+0
1
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| 1, 3, 9, 24, 66, 180, 468, 1206, 3150, 7998, 20124, 50520, 124044, 303906
(list; graph; listen)
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OFFSET
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0,2
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LINKS
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A. Aberkane, J. D. Currie, and N. Rampersad, The Number of Ternary Words Avoiding Abelian Cubes Grows Exponentially,J. Integer Sequences, Article 04.2.6, 2004,
Ali Aberkane & James D. Currie, The Number of Ternary Words Avoiding Abelian Cubes Grows Exponentially, Journal of Integer Sequences, Vol. 7 (2004), Article 04.2.7.
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EXAMPLE
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a(3) = 24, since the only abelian cubes of length 3 are 000, 111, 222
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CROSSREFS
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Sequence in context: A097134 A123892 A064831 this_sequence A051042 A121907 A118771
Adjacent sequences: A096165 A096166 A096167 this_sequence A096169 A096170 A096171
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KEYWORD
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hard,nonn
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AUTHOR
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Jeffrey Shallit (shallit(AT)graceland.uwaterloo.ca), Jun 19 2004
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