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

Author

Marks R. Nester

Keywords

• nonn

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]

Crossrefs

Cf. A054721.

Formula

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