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 A159722 #12 Jul 16 2020 07:56:00
%S A159722 12,576,17376,448800,10861056,253940736,5807161344,130675728384,
%T A159722 2903978803200,63887897001984,1393919508086784,30201597684350976,
%U A159722 650495989232173056,13939199950454784000,297369599774111563776,6319103998978368208896,133816319995412169621504
%N A159722 Number of permutations of 3 indistinguishable copies of 1..n arranged in a circle with exactly 2 local maxima.
%H A159722 Andrew Howroyd, <a href="/A159722/b159722.txt">Table of n, a(n) for n = 2..200</a>
%H A159722 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (52,-928,6784,-21760,25600).
%F A159722 a(n) = 3*n*(121*20^(n-2) + 15*4^(n-2) - 36*n*4^(n-2))/32. - _Andrew Howroyd_, May 10 2020
%F A159722 From _Colin Barker_, Jul 16 2020: (Start)
%F A159722 G.f.: 12*x*(1 + 2*x)*(1 - 6*x - 108*x^2 + 80*x^3) / ((1 - 4*x)^3*(1 - 20*x)^2).
%F A159722 a(n) = 52*a(n-1) - 928*a(n-2) + 6784*a(n-3) - 21760*a(n-4) + 25600*a(n-5) for n>6.
%F A159722 (End)
%o A159722 (PARI) a(n) = {3*n*(121*20^(n-2) + 15*4^(n-2) - 36*n*4^(n-2))/32} \\ _Andrew Howroyd_, May 10 2020
%o A159722 (PARI) Vec(12*x*(1 + 2*x)*(1 - 6*x - 108*x^2 + 80*x^3) / ((1 - 4*x)^3*(1 - 20*x)^2) + O(x^20)) \\ _Colin Barker_, Jul 16 2020
%Y A159722 Column k=3 of A334772.
%Y A159722 Cf. A159716.
%K A159722 nonn,easy
%O A159722 2,1
%A A159722 _R. H. Hardin_, Apr 20 2009
%E A159722 Terms a(9) and beyond from _Andrew Howroyd_, May 09 2020