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Period 2: repeat (1,10).
5

%I #40 Dec 18 2023 12:17:35

%S 1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,

%T 10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,1,10,

%U 1,10,1,10,1,10,1,10,1,10,1,10

%N Period 2: repeat (1,10).

%C Regular continued fraction of (5+sqrt 35)/10. - _R. J. Mathar_, Nov 21 2011

%C Sequence is an infinite palindrome in two ways (numbers and English names): ONE, TEN, ONE, TEN, ONE, TEN, ONE, ... . - _Eric Angelini_, Sep 16 2023

%H Vincenzo Librandi, <a href="/A010691/b010691.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).

%F a(n) = -9/2*(-1)^n + 11/2.

%F G.f.: (1+10*z)/(1-z^2). - _Zerinvary Lajos_, Feb 25 2009

%F a(n) = 10^n mod 11. - _M. F. Hasler_, Mar 10 2011

%F From _Nicolas Bělohoubek_, Nov 11 2021: (Start)

%F a(n) = 10/a(n-1). See also A010695.

%F a(n) = 11 - a(n-1). See also A010712. (End)

%p g:=(1+10*z)/((1-z^2)): gser:=series(g, z=0, 66): seq((coeff(gser, z, n)), n=0..65); # _Zerinvary Lajos_, Feb 25 2009

%t PadRight[{},100,{1,10}] (* _Harvey P. Dale_, Aug 27 2013 *)

%o (Magma) [10^n mod 11: n in [0..80]]; // _Vincenzo Librandi_, Aug 24 2011

%Y Cf. A036117, A070341, A168429, A070367, A070392, A070404, A048271, A187466.

%K nonn,easy,word

%O 0,2

%A _N. J. A. Sloane_