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A053563
Number of ternary Lyndon words of length n with trace 1 and subtrace 1 over GF(3). Same as the number of ternary Lyndon words of length n with trace 2 and subtrace 1 over GF(3).
5
0, 0, 1, 1, 4, 13, 36, 90, 243, 661, 1804, 4914, 13608, 37944, 106288, 298755, 843796, 2391363, 6797196, 19370696, 55345784, 158491993, 454803100, 1307541690, 3765720066, 10862667648, 31381059609, 90780846494, 262951527460
OFFSET
1,5
FORMULA
(1/n) Sum mu(d) M(n/d, 0, 2); d|n, d=1(3) + (1/n) Sum mu(d) M(n/d, 0, 1); d|n, d=2(3) where M(n, t, s) = Sum n!/(i!j!k!); i+j+k=n, j=t(3), k=s(3).
EXAMPLE
a(4) = 1 = |{ 0022 }|
CROSSREFS
KEYWORD
nonn
AUTHOR
Frank Ruskey, Jan 17 2000
STATUS
approved