This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A328657 #8 Nov 03 2019 15:49:10
%S A328657 0,0,1,1,4,9,26,66,183,488,1342,3690,10220,28470,79720,224230,633040,
%T A328657 1793727,5097638,14528640,41509364,118868750,341098474,980661510,
%U A328657 2824295364,8147015352,23535794889,68085719208,197213728060,571919889400,1660412355602,4825573629390
%N A328657 Number of primitive (period n) n-bead bracelet structures which are not periodic palindromes using a maximum of three different colored beads.
%C A328657 Permuting the colors of the beads will not change the structure.
%H A328657 Andrew Howroyd, <a href="/A328657/b328657.txt">Table of n, a(n) for n = 1..200</a>
%F A328657 a(n) = Sum_{k=1..3} A309784(n, k).
%F A328657 a(n) = A056362(n) - A056514(n).
%e A328657 For n <= 5, the structures are the same as in A328038.
%e A328657 For n = 6, the 9 bracelet structures have the patterns: AABABB, ABCCCC, ABBCCC, ABBBCB, ABBCBC, ABBCCB, ABCBBC, AABBCC, AABCBC.
%Y A328657 Cf. A056362, A056514, A309784, A328038.
%K A328657 nonn
%O A328657 1,5
%A A328657 _Andrew Howroyd_, Oct 24 2019