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 A159711 #18 Sep 08 2022 08:45:44
%S A159711 0,0,0,0,0,0,96,1904,23040,221184,1858560,14353152,104742912,
%T A159711 734769152,5010432000,33464217600,220066480128,1430279159808,
%U A159711 9212045819904,58914039332864,374665295953920,2371935399837696,14960708435312640,94072038170296320,589975504803594240
%N A159711 Number of permutations of 1..n arranged in a circle with exactly 3 local maxima.
%H A159711 Alois P. Heinz, <a href="/A159711/b159711.txt">Table of n, a(n) for n = 0..1000</a>
%H A159711 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (32,-444,3504,-17328,55680,-116288,152320,-113664,36864).
%F A159711 G.f.: -16*(144*x^4-444*x^3+296*x^2-73*x+6)*x^6 / ((6*x-1)^2 *(4*x-1)^3 *(2*x-1)^4). - _Alois P. Heinz_, Oct 26 2015
%F A159711 a(n) = 1/3*2^(-6+n)*n*(15+3*2^(1+n)+3^n-3*(8+2^n)*n+6*n^2) for n>1. - _Colin Barker_, Oct 26 2015
%t A159711 Table[(1/3)*2^(-6+n)*n*(15+3*2^(1+n)+3^n-3*(8+2^n)*n+6*n^2), {n,0,30}] (* _G. C. Greubel_, Jun 01 2018 *)
%o A159711 (PARI) a(n) = if(n==1, 0, 1/3*2^(-6+n)*n*(15+3*2^(1+n)+3^n-3*(8+2^n)*n +6*n^2)) \\ _Colin Barker_, Oct 26 2015
%o A159711 (PARI) concat(vector(6), Vec(-16*x^6*(144*x^4-444*x^3+296*x^2-73*x+6)/(
%o A159711 (2*x-1)^4*(4*x-1)^3*(6*x-1)^2) + O(x^30))) \\ _Colin Barker_, Oct 26 2015
%o A159711 (Magma) [(1/3)*2^(-6+n)*n*(15+3*2^(1+n)+3^n-3*(8+2^n)*n+6*n^2): n in [0..30]]; // _G. C. Greubel_, Jun 01 2018
%Y A159711 Column k=3 of A263789.
%K A159711 nonn,easy
%O A159711 0,7
%A A159711 _R. H. Hardin_, Apr 20 2009
%E A159711 a(17)-a(24) from _Alois P. Heinz_, Oct 26 2015