%I #23 Dec 12 2023 09:34:17
%S 0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,
%T 2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,
%U 0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4,0,1,2,4
%N Period 4: repeat [0, 1, 2, 4].
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1).
%F a(n+4) = a(n).
%F a(n) = floor((5*n+1)/4) mod 5. - _Gary Detlefs_, May 15 2011
%F From _Bruno Berselli_, May 16 2011: (Start)
%F G.f.: x*(1+2*x+4*x^2)/(1-x^4).
%F a(n) = (5-(-1)^n)*(6-2*I^(n*(n-1)))/8-2. (End)
%F From _Wesley Ivan Hurt_, Jul 09 2016: (Start)
%F a(n) = (7-3*I^(2*n)-(2+3*I)*I^(-n)-(2-3*I)*I^n)/4.
%F a(n) = (7-3*cos(n*Pi)-4*cos(n*Pi/2)-6*sin(n*Pi/2)-3*I*sin(n*Pi))/4. (End)
%p seq(op([0, 1, 2, 4]), n=0..40); # _Wesley Ivan Hurt_, Jul 09 2016
%t PadRight[{}, 100, {0, 1, 2, 4}] (* _Wesley Ivan Hurt_, Jul 09 2016 *)
%o (Magma) &cat [[0, 1, 2, 4]^^30]; // _Wesley Ivan Hurt_, Jul 09 2016
%K nonn,easy
%O 0,3
%A _Paul Curtz_, Jun 21 2007
%E Name rewritten by _Bruno Berselli_, May 16 2011