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 A053563 #9 May 03 2019 07:49:02
%S A053563 0,0,1,1,4,13,36,90,243,661,1804,4914,13608,37944,106288,298755,
%T A053563 843796,2391363,6797196,19370696,55345784,158491993,454803100,
%U A053563 1307541690,3765720066,10862667648,31381059609,90780846494,262951527460
%N A053563 Number of ternary Lyndon words of length n with trace 1 and subtrace 1 over GF(3). Same as the number of ternary Lyndon words of length n with trace 2 and subtrace 1 over GF(3).
%H A053563 F. Ruskey, <a href="http://combos.org/TSlyndonF3">Ternary Lyndon words with given trace and subtrace over GF(3)</a>
%F A053563 (1/n) Sum mu(d) M(n/d, 0, 2); d|n, d=1(3) + (1/n) Sum mu(d) M(n/d, 0, 1); d|n, d=2(3) where M(n, t, s) = Sum n!/(i!j!k!); i+j+k=n, j=t(3), k=s(3).
%e A053563 a(4) = 1 = |{ 0022 }|
%Y A053563 Cf. A053548, A053560, A053561, A053562, A053564.
%K A053563 nonn
%O A053563 1,5
%A A053563 _Frank Ruskey_, Jan 17 2000