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 A010691 #40 Dec 18 2023 12:17:35
%S A010691 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 A010691 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 A010691 1,10,1,10,1,10,1,10,1,10,1,10
%N A010691 Period 2: repeat (1,10).
%C A010691 Regular continued fraction of (5+sqrt 35)/10. - _R. J. Mathar_, Nov 21 2011
%C A010691 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 A010691 Vincenzo Librandi, <a href="/A010691/b010691.txt">Table of n, a(n) for n = 0..1000</a>
%H A010691 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010691 a(n) = -9/2*(-1)^n + 11/2.
%F A010691 G.f.: (1+10*z)/(1-z^2). - _Zerinvary Lajos_, Feb 25 2009
%F A010691 a(n) = 10^n mod 11. - _M. F. Hasler_, Mar 10 2011
%F A010691 From _Nicolas Bělohoubek_, Nov 11 2021: (Start)
%F A010691 a(n) = 10/a(n-1). See also A010695.
%F A010691 a(n) = 11 - a(n-1). See also A010712. (End)
%p A010691 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 A010691 PadRight[{},100,{1,10}] (* _Harvey P. Dale_, Aug 27 2013 *)
%o A010691 (Magma) [10^n mod 11: n in [0..80]]; // _Vincenzo Librandi_, Aug 24 2011
%Y A010691 Cf. A036117, A070341, A168429, A070367, A070392, A070404, A048271, A187466.
%K A010691 nonn,easy,word
%O A010691 0,2
%A A010691 _N. J. A. Sloane_