A056277 Number of primitive (aperiodic) word structures of length n using a 6-ary alphabet.

1, 1, 4, 13, 51, 197, 875, 4096, 20643, 109246, 601491, 3402911, 19628063, 114699438, 676207572, 4010086352, 23874362199, 142508702805, 852124263683, 5101098123207, 30560194492576, 183176169456214

Offset

1,3

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..22.

Formula

sum mu(d)*A056273(n/d) where d|n and n>0.

Crossrefs

Cf. A054721.

Sequence in context: A149461 A056276 A144035 * A082951 A135345 A149462

Adjacent sequences: A056274 A056275 A056276 * A056278 A056279 A056280

Keyword

nonn

Author

Marks R. Nester

Status

approved