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%I #42 Mar 08 2024 01:11:56
%S 1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,
%T 2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,
%U 2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2,1,2,1,1,1,2
%N Period 6: repeat [1, 1, 2, 1, 2, 1].
%C Decimal expansion of 112121/999999. - _Klaus Brockhaus_, May 21 2010
%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,1).
%F G.f.: (1+x+2*x^2+x^3+2*x^4+x^5)/((1-x)*(1+x)*(x^2+x+1)*(x^2-x+1)). - _R. J. Mathar_, Jan 17 2008
%F From _Wesley Ivan Hurt_, Jun 17 2016: (Start)
%F a(n) = a(n-6) for n>5.
%F a(n) = (4 + cos(n*Pi) - cos(n*Pi/3) - cos(2*n*Pi/3))/3. (End)
%p A131718:=n->(4+cos(n*Pi)-cos(n*Pi/3)-cos(2*n*Pi/3))/3: seq(A131718(n), n=0..100); # _Wesley Ivan Hurt_, Jun 17 2016
%t Flatten[Table[{1, 1, 2, 1, 2, 1}, {20}]] (* _Wesley Ivan Hurt_, Jun 17 2016 *)
%o (Magma) &cat[[1, 1, 2, 1, 2, 1]: k in [1..30]] // _Vincenzo Librandi_, Nov 23 2010
%o (PARI) a(n)=[1,1,2,1,2,1][n%6+1] \\ _Charles R Greathouse IV_, Jun 02 2011
%Y Cf. A178149 (decimal expansion of (15+sqrt(1365))/30). - _Klaus Brockhaus_, May 21 2010
%K nonn,easy,less
%O 0,3
%A _Paul Curtz_, Sep 15 2007
%E More terms from _Klaus Brockhaus_, May 21 2010
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