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

Author

Andrew Howroyd, Oct 24 2019

Keywords

• nonn

Comments

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

Examples

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

Links

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

Crossrefs

Cf. A056363, A056515, A309784, A328039.

Formula

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

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