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 A270824 #39 Sep 16 2017 19:34:41
%S A270824 0,1,1,0,2,3,3,2,3,2,2,3,1,0,0,1,0,1,1,0,2,3,3,2,3,2,2,3,1,0,0,1,0,1,
%T A270824 1,0,2,3,3,2,3,2,2,3,1,0,0,1,0,1,1,0,2,3,3,2,3,2,2,3,1,0,0,1,0,1,1,0,
%U A270824 2,3,3,2,3,2,2,3,1,0,0,1,0,1,1,0,2,3,3,2,3,2,2,3,1,0,0,1
%N A270824 Period 16: repeat [0, 1, 1, 0, 2, 3, 3, 2, 3, 2, 2, 3, 1, 0, 0, 1].
%H A270824 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,-1,1).
%F A270824 a(n) = (floor((n+4)/4) - [floor(n/4) + floor((n+4)/4)] * [(floor((n+12)/8)) mod 2 * (floor((n+3)/2)) mod 2 + (floor((n+4)/8)) mod 2 * (floor((n+1)/2)) mod 2]) mod 4.
%F A270824 From _Chai Wah Wu_, Jun 04 2016: (Start)
%F A270824 a(n) = a(n-1) - a(n-8) + a(n-9) for n > 8.
%F A270824 G.f.: x*(1 - x^2 + 2*x^3 + x^4 - x^6 + x^7)/((1 - x)*(1 + x^8)). (End)
%t A270824 PadRight[{},120,{0,1,1,0,2,3,3,2,3,2,2,3,1,0,0,1}] (* _Harvey P. Dale_, Sep 16 2017 *)
%o A270824 (PARI) a(n)=[0, 1, 1, 0, 2, 3, 3, 2, 3, 2, 2, 3, 1, 0, 0, 1][n%16+1] \\ _Charles R Greathouse IV_, Jul 17 2016
%Y A270824 Cf. A270823.
%K A270824 nonn,easy
%O A270824 0,5
%A A270824 _William Walkington_, Mar 23 2016