login
A328658
Number of primitive (period n) n-bead bracelet structures which are not periodic palindromes using a maximum of four different colored beads.
2
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
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
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Oct 24 2019
STATUS
approved