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 A056466 #9 Sep 29 2019 11:10:56
%S A056466 0,0,0,0,0,0,0,0,120,120,1800,1800,16800,16800,126000,126000,834120,
%T A056466 834000,5103000,5102880,29607600,29605800,165528000,165526200,
%U A056466 901020120,901003320,4809004080,4808987400,25292030400,25291904280,131542866000,131542740000
%N A056466 Number of primitive (aperiodic) palindromes using exactly five different symbols.
%D A056466 M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]
%H A056466 Andrew Howroyd, <a href="/A056466/b056466.txt">Table of n, a(n) for n = 1..200</a>
%F A056466 a(n) = Sum_{d|n} mu(d)*A056456(n/d).
%Y A056466 Column 5 of A327873.
%Y A056466 Cf. A056456, A056461.
%K A056466 nonn
%O A056466 1,9
%A A056466 _Marks R. Nester_
%E A056466 Terms a(30) and beyond from _Andrew Howroyd_, Sep 29 2019