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

Author

Marks R. Nester

Keywords

• nonn

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]

Crossrefs

Cf. A056316.

Formula

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