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A046209
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Number of ternary Lyndon words whose digits sum to 0 mod 3; also number of trace 0 irreducible polynomials over GF(3).
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10
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1, 1, 2, 6, 16, 38, 104, 270, 726, 1960, 5368, 14736, 40880, 113828, 318848, 896670, 2532160, 7174050, 20390552, 58112088, 166037248, 475467916, 1364393896, 3922624800, 11297181456, 32588003000, 94143178098, 272342710380
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| Also number of ternary Lyndon words of trace 0 over GF(3).
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LINKS
| Index entries for sequences related to Lyndon words
F. Ruskey, Number of q-ary Lyndon words with given trace mod q
F. Ruskey, Number of monic irreducible polynomials over GF(q) with zero trace ...
F. Ruskey, Number of Lyndon words of given trace
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FORMULA
| ( Sum_{d|n} gcd(d, 3)*mu(d)*3^{n/d}) / (3n)
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EXAMPLE
| a(4)= 6 = |{ 0012, 0021, 0111, 0102, 0222, 1122 }|
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CROSSREFS
| Cf. A046211.
Sequence in context: A167821 A093041 A156616 * A198951 A078774 A174016
Adjacent sequences: A046206 A046207 A046208 * A046210 A046211 A046212
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KEYWORD
| nonn
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AUTHOR
| Frank Ruskey (ruskey(AT)cs.uvic.ca), Dec 13 1999
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