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 A285042 #8 Oct 02 2019 12:07:20
%S A285042 1,1,1,1,3,4,10,14,36,50,138,202,562,876,2589,4134,12828,21146,69115,
%T A285042 115974,398619,678554,2450202,4213596,15939338,27644432,109304036,
%U A285042 190899270,787013630,1382958544,5931819804,10480142146,46673246440,82864869600,382473261356
%N A285042 Number of primitive (period n) periodic palindromic structures of length n using an infinite alphabet.
%C A285042 See A285037 for additional information. Permuting the symbols will not change the structure.
%H A285042 Andrew Howroyd, <a href="/A285042/b285042.txt">Table of n, a(n) for n = 0..500</a>
%F A285042 a(n) = Sum_{d | n} mu(n/d) * A285013(d) for n > 0.
%o A285042 (PARI) \\ Requires T from A285037.
%o A285042 seq(n)={my(A=T(n)); concat([1], vector(n, i, vecsum(A[i, ])))} \\ _Andrew Howroyd_, Oct 02 2019
%Y A285042 Row sums of A285037.
%Y A285042 Cf. A285013.
%K A285042 nonn
%O A285042 0,5
%A A285042 _Andrew Howroyd_, Apr 08 2017
%E A285042 a(0)=1 prepended and terms a(28) and beyond from _Andrew Howroyd_, Oct 02 2019