A056314 Number of primitive (aperiodic) reversible strings with n beads using a maximum of three different colors.

3, 3, 15, 39, 132, 357, 1131, 3276, 9945, 29508, 88935, 265668, 798252, 2391441, 7177584, 21523320, 64579920, 193709763, 581160255, 1743392040, 5230264026, 15690529437, 47071855131, 141214764600

Offset

1,1

Comments

A string and its reverse are considered to be equivalent.

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..24.

Formula

Sum mu(d)*A032120(n/d) where d|n.

Crossrefs

Column 3 of A284871.

Cf. A045625.

Sequence in context: A035617 A126319 A165553 * A171379 A373692 A078631

Adjacent sequences: A056311 A056312 A056313 * A056315 A056316 A056317

Keyword

nonn

Author

Marks R. Nester

Status

approved