A056276 Number of primitive (aperiodic) word structures of length n using a 5-ary alphabet.

1, 1, 4, 13, 51, 196, 854, 3830, 17997, 86419, 422004, 2079260, 10306751, 51263086, 255514299, 1275160060, 6368612301, 31821454413, 159042661904, 795019250650, 3974515029793, 19870830290476, 99348921288654, 496728909635860, 2483597478617750, 12417846151236799

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..26.

Formula

a(n) = Sum_{d|n} mu(d)*A056272(n/d).

Crossrefs

Cf. A008683, A054720.

Sequence in context: A219579 A300122 A149461 * A144035 A056277 A082951

Adjacent sequences: A056273 A056274 A056275 * A056277 A056278 A056279

Keyword

nonn

Author

Marks R. Nester

Status

approved