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 A053548 Number of ternary Lyndon words of length n with trace 0 and subtrace 0 over GF(3). 5
 1, 0, 0, 2, 4, 9, 32, 90, 240, 654, 1804, 4950, 13664, 37944, 106272, 298890, 843796, 2390595, 6796160, 19370696, 55345680, 158489298, 454803100, 1307556162, 3765741324, 10862667648, 31381058880, 90780903460, 262951527460 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Trace is sum of digits, subtrace is sum of products of pairs of digits. [3|n] above is "Iversonian convention", 1 if 3|n, 0 otherwise. LINKS FORMULA Sum{ d divides n, d==1, 2(3) }mu(d)(M(n/d, 0, 0)-[3d divides n]3^{n/(3d)}), where M(n, t, s) = Sum{ i+j+k=n, j=t(3), k=s(3) }( n!/(i!j!k!) ) EXAMPLE a(4) = 2 = |{ 0111, 0222 }| CROSSREFS Cf. A053560, A053561, A053562, A053563, A053564. Sequence in context: A243789 A214935 A092329 * A054119 A259490 A274758 Adjacent sequences:  A053545 A053546 A053547 * A053549 A053550 A053551 KEYWORD nonn AUTHOR Frank Ruskey, Jan 16 2000 STATUS approved

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Last modified September 23 04:54 EDT 2020. Contains 337295 sequences. (Running on oeis4.)