A056317 Number of primitive (aperiodic) reversible strings with n beads using a maximum of six different colors.

6, 15, 120, 645, 3990, 23295, 140610, 839790, 5042610, 30232965, 181421850, 1088390415, 6530486970, 39182081385, 235093327980, 1410554953080, 8463334761210, 50779978307010, 304679900238330

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..19.

Formula

sum mu(d)*A056308(n/d) where d|n.

Crossrefs

Column 6 of A284871.

Cf. A045625.

Sequence in context: A372990 A219771 A087137 * A129421 A013227 A013223

Adjacent sequences: A056314 A056315 A056316 * A056318 A056319 A056320

Keyword

nonn

Author

Marks R. Nester

Status

approved