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 A056514 #15 Oct 01 2019 19:04:27
%S A056514 1,1,1,1,3,4,9,13,28,39,84,121,244,364,741,1088,2200,3280,6591,9841,
%T A056514 19720,29510,59169,88573,177240,265716,531804,797121,1594684,2391484,
%U A056514 4783968,7174453,14350000,21523238,43050000,64570064,129143196,193710244,387430329,581130368,1162271280
%N A056514 Number of primitive (period n) periodic palindromic structures using a maximum of three different symbols.
%C A056514 For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome. Permuting the symbols will not change the structure.
%D A056514 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 A056514 Andrew Howroyd, <a href="/A056514/b056514.txt">Table of n, a(n) for n = 0..200</a>
%F A056514 a(n) = Sum_{d|n} mu(d)*A056504(n/d) for n > 0.
%F A056514 Moebius transform of A056504.
%F A056514 a(n) = Sum_{k=1..3} A285037(n, k) for n > 0. - _Andrew Howroyd_, Apr 08 2017
%Y A056514 Cf. A056477, A056504, A285037.
%K A056514 nonn
%O A056514 0,5
%A A056514 _Marks R. Nester_
%E A056514 Corrected by _Franklin T. Adams-Watters_ and _T. D. Noe_, Oct 25 2006
%E A056514 a(17)-a(35) from _Andrew Howroyd_, Apr 08 2017
%E A056514 a(0)=1 prepended and terms a(36) and beyond from _Andrew Howroyd_, Oct 01 2019