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 A144476 #13 Jun 13 2015 00:52:41
%S A144476 1,1,-1,3,-2,-2,2,1,-3,-3,3,-2,-1,-1,1,-3,2,2,-2,-1,3,3,-3,2,1,1,-1,3,
%T A144476 -2,-2,2,1,-3,-3,3,-2,-1,-1,1,-3,2,2,-2,-1,3,3,-3,2,1,1,-1
%N A144476 Four interlaced copies of A117373.
%H A144476 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1,0,0,0,-1).
%F A144476 a(n)=a(n-4)-a(n-8). a(4n+1)=a(4n+2)=A117373(n). a(4n+3)=A117373(n+3). a(4n+4)=A117373(n+5). [From _R. J. Mathar_, Dec 08 2008]
%F A144476 G.f.: -x*(2*x^7-3*x^6+3*x^5+3*x^4-3*x^3+x^2-x-1) / (x^8-x^4+1). - _Colin Barker_, Apr 11 2013
%t A144476 Clear[M, v, n, a] M[0] = {{0, -1}, {1, 1}}; M[1] = {{1, 0}, {1, 1}}; M[2] = {{-1, 0}, {1, 1}}; M[3] = {{0, 1}, {1, 1}}; v[0] = {1, 1}; v[n_] := v[n] = M[Mod[n, 4]].v[n - 1]; a = Table[v[n][[1]], {n, 0, 50}]
%K A144476 sign,easy
%O A144476 1,4
%A A144476 _Roger L. Bagula_ and _Gary W. Adamson_, Oct 10 2008