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A056282 Number of primitive (aperiodic) word structures of length n which contain exactly six different symbols. 1
0, 0, 0, 0, 0, 1, 21, 266, 2646, 22827, 179487, 1323651, 9321312, 63436352, 420693273, 2734926292, 17505749898, 110687248392, 693081601779, 4306078872557, 26585679462783, 163305339165738, 998969857983405 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

COMMENTS

Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same structure.

REFERENCES

M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]

LINKS

Table of n, a(n) for n=1..23.

FORMULA

a(n) = Sum_{n > 0, d|n} mu(d)*A000770(n/d).

CROSSREFS

Column 6 of A137651.

Cf. A056271.

Sequence in context: A169895 A092794 A133717 * A000770 A133105 A215766

Adjacent sequences:  A056279 A056280 A056281 * A056283 A056284 A056285

KEYWORD

nonn

AUTHOR

Marks R. Nester

STATUS

approved

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Last modified November 20 02:57 EST 2018. Contains 317371 sequences. (Running on oeis4.)