A328658 Number of primitive (period n) n-bead bracelet structures which are not periodic palindromes using a maximum of four different colored beads.

0, 0, 1, 2, 6, 19, 58, 195, 651, 2294, 8122, 29607, 108276, 401389, 1494268, 5600204, 21065520, 79567572, 301448098, 1145448216, 4363328350, 16659757647, 63740548126, 244337865925, 938252884294, 3608661283038, 13900010654999, 53614312021527, 207062098878276

Offset

1,4

Comments

Permuting the colors of the beads will not change the structure.

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

Formula

a(n) = Sum_{k=1..4} A309784(n, k).

a(n) = A056363(n) - A056515(n).

Example

For n = 4, the 2 bracelet structures are: AABC, ABCD.
For n = 5, the 6 bracelet structures are: AAABC, AABAC, AABBC, ABABC, AABCD, ABACD.

Crossrefs

Cf. A056363, A056515, A309784, A328039.

Sequence in context: A325918 A307564 A308240 * A067675 A037512 A111277

Adjacent sequences: A328655 A328656 A328657 * A328659 A328660 A328661

Keyword

nonn

Author

Andrew Howroyd, Oct 24 2019

Status

approved