%I #15 Sep 08 2022 08:45:59
%S 0,1,2,3,4,4,5,6,7,7,8,9,10,10,11,12,13,13,14,15,16,17,17,18,19,20,20,
%T 21,22,23,23,24,25,26,26,27,28,29,30,30,31,32,33,33,34,35,36,36,37,38,
%U 39,39,40,41,42,43,43,44,45,46,46,47,48,49,49,50,51,52,52,53
%N a(n) = 4*n - floor(2*n*r), where r=(1+sqrt(5))/2 (the golden ratio).
%H Vincenzo Librandi, <a href="/A195172/b195172.txt">Table of n, a(n) for n = 0..10000</a>
%F a(n) = A189663(2n). - _R. J. Mathar_, Sep 11 2011
%t With[{c = GoldenRatio}, Table[4*n - Floor[2*c*n], {n,0,50}]] (* _G. C. Greubel_, Oct 31 2017 *)
%o (Magma) [4*n-Floor(n*(1+Sqrt(5))): n in [0..70]]; // _Vincenzo Librandi_, Sep 11 2011
%o (PARI) for(n=0,50, print1(4*n - floor(n*(1+sqrt(5))), ", ")) \\ _G. C. Greubel_, Oct 31 2017
%K nonn
%O 0,3
%A _Clark Kimberling_, Sep 10 2011