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 A056523 #13 Oct 01 2019 19:53:56 %S A056523 0,0,0,0,0,0,0,0,0,1,1,13,21,154,266,1488,2646,12857,22827,101484, %T A056523 179487,752646,1323652,5325226,9321312,36387267,63436373,242085494, %U A056523 420693273,1577870839,2734926558,10120484024,17505749897,64096919293,110687251039,401885411487 %N A056523 Number of primitive (period n) periodic palindromic structures using exactly six different symbols. %D A056523 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 A056523 Andrew Howroyd, <a href="/A056523/b056523.txt">Table of n, a(n) for n = 1..200</a> %F A056523 a(n) = A056517(n) - A056516(n). %F A056523 Moebius transform of A056512. - _Andrew Howroyd_, Oct 01 2019 %e A056523 For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome. Permuting the symbols will not change the structure. This should be different from A056512. %Y A056523 Column 6 of A285037. %Y A056523 Cf. A056485, A056512, A056516, A056517. %K A056523 nonn %O A056523 1,12 %A A056523 _Marks R. Nester_ %E A056523 a(16)-a(26) from _Andrew Howroyd_, Apr 09 2017 %E A056523 Terms a(27) and beyond from _Andrew Howroyd_, Oct 01 2019