A056366 Number of primitive (period n) bracelet structures using exactly two different colored beads.

0, 1, 1, 2, 3, 5, 8, 14, 21, 39, 62, 112, 189, 352, 607, 1144, 2055, 3885, 7154, 13602, 25472, 48670, 92204, 176770, 337590, 649341, 1246840, 2404872, 4636389, 8964143, 17334800

Offset

1,4

Comments

Turning over will not create a new bracelet. Permuting the colors of the beads will not change the structure. Identical to A000046 for n>1.

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..31.

Formula

A000046(n)-A000007(n-1).

Crossrefs

Column 2 of A276543.

Cf. A056303.

Sequence in context: A034416 A306912 A212607 * A000046 A293641 A293553

Adjacent sequences: A056363 A056364 A056365 * A056367 A056368 A056369

Keyword

nonn

Author

Marks R. Nester

Status

approved