A056334 Number of primitive (aperiodic) reversible string structures with n beads using a maximum of five different colors.

1, 1, 3, 9, 31, 111, 454, 1982, 9130, 43547, 211658, 1041316, 5156641, 25640000, 127773440, 637622320, 3184387573, 15910938734, 79521737938, 397510683092, 1987259549544, 9935420434636, 49674470817194

Offset

1,3

Comments

A string and its reverse are considered to be equivalent. Permuting the colors will not change the 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

Sum mu(d)*A056324(n/d) where d|n.

Crossrefs

Cf. A056316.

Sequence in context: A209335 A049159 A101473 * A063032 A056335 A276549

Adjacent sequences: A056331 A056332 A056333 * A056335 A056336 A056337

Keyword

nonn

Author

Marks R. Nester

Status

approved