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 A108014 #21 Jun 13 2015 00:51:50
%S A108014 0,2,3,4,5,8,14,24,39,62,99,160,260,422,683,1104,1785,2888,4674,7564,
%T A108014 12239,19802,32039,51840,83880,135722,219603,355324,574925,930248,
%U A108014 1505174,2435424,3940599,6376022,10316619,16692640,27009260,43701902
%N A108014 Expansion of (x^2-2*x)/(x^4-x^2+2*x-1).
%H A108014 Fumio Hazama, <a href="http://dx.doi.org/10.1016/j.disc.2011.06.008">Spectra of graphs attached to the space of melodies</a>, Discr. Math., 311 (2011), 2368-2383. See Table 2.1.
%H A108014 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,1).
%F A108014 M = {{0, 0, 0, 1}, {1, 1, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 1}} v[n]=v[n-1].M a(n) = v[n][[1]].
%F A108014 a(n) = (1/2)*[Lucas(n+1) + 2*cos((n+4)*Pi/3)].
%F A108014 a(n) = (1/2)*[A000032(n+1) + A057079(n+5)].
%F A108014 a(0)=0, a(1)=2, a(2)=3, a(3)=4, a(n) = 2*a(n-1)-a(n-2)+a(n-4). [_Harvey P. Dale_, Aug 19 2011]
%t A108014 M = {{0, 0, 0, 1}, {1, 1, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 1}} v[1] = {0, 1, 1, 2}; v[n_] := v[n] = M.v[n - 1]; digits = 50; a = Table[v[n][[1]], {n, 1, digits}]
%t A108014 CoefficientList[Series[(x^2-2x)/(x^4-x^2+2x-1),{x,0,40}],x] (* or *) LinearRecurrence[{2,-1,0,1},{0,2,3,4},41] (* _Harvey P. Dale_, Aug 19 2011 *)
%o A108014 (PARI) Vec((x^2-2*x)/(x^4-x^2+2*x-1)+O(x^99)) \\ _Charles R Greathouse IV_, Sep 27 2012
%K A108014 nonn,easy
%O A108014 0,2
%A A108014 _Roger L. Bagula_, May 30 2005