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 A330307 #13 Dec 11 2019 12:08:55
%S A330307 3,3,2,9,18,20,24,36,24,108,468,1554,4308,10128,21144,40080,68496,
%T A330307 105840,153120,206976,259648,317952
%N A330307 Number of circular ternary words of length n having the maximum possible number of distinct blocks of length floor(log_3 n) and floor(log_3 n)+1.
%C A330307 A circular word (a.k.a. "necklace") can be viewed as a representative of the equivalence class under cyclic shift.
%C A330307 The words counted by this sequence have 3^i distinct blocks of length i = floor(log_3 n) and n distinct blocks of length i+1.
%C A330307 This sequence counts a certain natural generalization of ternary de Bruijn words, which are cyclic words of length 3^n containing all n-length blocks as subwords.
%H A330307 D. Gabric, S. Holub, and J. Shallit, <a href="https://arxiv.org/abs/1903.05442">Generalized de Bruijn words and the state complexity of conjugate sets</a>, arXiv:1903.05442 [cs.FL], March 13 2019.
%e A330307 For n = 5 the 18 strings are those arising from applying all permutations of the alphabet to {00102, 00112, 00121, 00122, 01022, 01102, 01121, 01122, 01211, 01221} and selecting the lexicographically least representative up to shift.
%Y A330307 The ternary analog of A317586.
%K A330307 nonn,more
%O A330307 1,1
%A A330307 _Jeffrey Shallit_, Dec 10 2019