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 A270823 #41 Feb 21 2024 16:37:27
%S A270823 0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1,0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1,0,2,
%T A270823 3,1,1,3,2,0,1,3,2,0,0,2,3,1,0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1,0,2,3,1,
%U A270823 1,3,2,0,1,3,2,0,0,2,3,1,0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1
%N A270823 Period 16: repeat [0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1].
%C A270823 Decimal expansion of 700330007/30300000303. - _Elmo R. Oliveira_, Feb 21 2024
%H A270823 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (1,-1,1,0,0,0,0,-1,1,-1,1).
%F A270823 a(n) = (n+1+(15-2n)*[(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 A270823 From _Chai Wah Wu_, Jun 04 2016: (Start)
%F A270823 a(n) = a(n-1) - a(n-2) + a(n-3) - a(n-8) + a(n-9) - a(n-10) + a(n-11) for n > 10.
%F A270823 G.f.: x*(2 + x + x^3 - x^5 + 2*x^8 + x^9)/((1 - x)*(1 + x^2)*(1 + x^8)). (End)
%t A270823 PadRight[{},120,{0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1}] (* _Harvey P. Dale_, May 17 2017 *)
%o A270823 (PARI) a(n)=[0,2,3,1,1,3,2,0,1,3,2,0,0,2,3,1][n%16+1] \\ _Charles R Greathouse IV_, Jul 17 2016
%Y A270823 Cf. A270824.
%K A270823 nonn,easy
%O A270823 0,2
%A A270823 _William Walkington_, Mar 23 2016