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 A056464 #13 Sep 29 2019 11:39:55
%S A056464 0,0,0,0,6,6,36,36,150,144,540,534,1806,1770,5790,5760,18150,17994,
%T A056464 55980,55830,170970,170466,519156,518580,1569744,1567944,4733670,
%U A056464 4732014,14250606,14244660,42850116,42844320,128746410,128728800
%N A056464 Number of primitive (aperiodic) palindromes using exactly three different symbols.
%D A056464 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 A056464 Andrew Howroyd, <a href="/A056464/b056464.txt">Table of n, a(n) for n = 1..200</a>
%F A056464 a(n) = Sum_{d|n} mu(d)*A056454(n/d).
%p A056464 with(numtheory):with(combinat,stirling2):A056454:=n->3!*stirling2(floor((n+1)/2),3);A056464:=n->add(mobius(d)*A056454(n/d),d=divisors(n)); # C. Ronaldo
%Y A056464 Column 3 of A327873.
%Y A056464 Cf. A056454, A056459.
%K A056464 nonn
%O A056464 1,5
%A A056464 _Marks R. Nester_