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 A166593 #12 May 18 2016 12:02:30
%S A166593 0,1,4,6,9,10,10,9,6,4,1,0,0,1,4,6,9,10,10,9,6,4,1,0,0,1,4,6,9,10,10,
%T A166593 9,6,4,1,0,0,1,4,6,9,10,10,9,6,4,1,0,0,1,4,6,9,10,10,9,6,4,1,0,0,1,4,
%U A166593 6,9,10,10,9,6,4,1,0,0,1,4,6,9,10,10,9,6,4,1,0,0,1,4,6,9,10,10,9,6,4,1,0,0
%N A166593 Partial sums of A166592.
%H A166593 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1,-1,1).
%F A166593 G.f.: x(1+3x+x^2)/((1-x)(1-x^2+x^4)) = x(1+3x+x^2)/(1-x-x^2+x^3+x^4-x^5).
%F A166593 a(n) = a(n-1) + a(n-2) - a(n-3) - a(n-4) + a(n-5).
%F A166593 a(n) = (sqrt(8) - sqrt(6))*cos(5*Pi*n/6 + 5*Pi/12)-(sqrt(8) + sqrt(6))*cos(Pi*n/6 + Pi/12) + 5.
%F A166593 a(n + 12) = a(n). - _G. C. Greubel_, May 18 2016
%t A166593 LinearRecurrence[{1,1,-1,-1,1}, {0,1,4,6,9}, 25] (* _G. C. Greubel_, May 18 2016 *)
%K A166593 easy,nonn
%O A166593 0,3
%A A166593 _Paul Barry_, Oct 17 2009