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A053561 Number of ternary Lyndon words of length n with trace 0 and subtrace 2 over GF(3). 5
0, 1, 2, 3, 6, 15, 36, 87, 234, 645, 1782, 4893, 13608, 37994, 106434, 299025, 844182, 2391723, 6797196, 19369708, 55342972, 158486625, 454795398, 1307534319, 3765720066, 10862688116, 31381118658, 90780960426, 262951692390 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..29.

F. Ruskey, Ternary Lyndon words of given trace and subtrace over GF(3)

FORMULA

(1/n) Sum mu(d) M(n/d, 1, 1); d divides n, d=1(3) + (1/n) Sum mu(d) M(n/d, 2, 2); d divides 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) = 3 = |{ { 0012, 0021, 0102 }|

CROSSREFS

Cf. A053548, A053560, A053562, A053563, A053564.

Sequence in context: A138477 A182240 A052102 * A237585 A147773 A006403

Adjacent sequences:  A053558 A053559 A053560 * A053562 A053563 A053564

KEYWORD

nonn

AUTHOR

Frank Ruskey, Jan 17 2000

STATUS

approved

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Last modified April 21 21:03 EDT 2018. Contains 302877 sequences. (Running on oeis4.)