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 A010699 #27 Dec 14 2023 06:06:36
%S A010699 2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,
%T A010699 2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,2,9,
%U A010699 2,9,2,9,2,9,2,9,2,9,2,9,2
%N A010699 Period 2: repeat (2,9).
%C A010699 Continued fraction of 1 + sqrt(11)/3 = A176056. - _R. J. Mathar_, Nov 21 2011
%H A010699 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010699 a(n) = -7/2*(-1)^n+11/2. - _Paolo P. Lava_, Oct 20 2006
%F A010699 G.f.: (2+9x)/((1-x)(1+x)). - _R. J. Mathar_, Nov 21 2011
%F A010699 a(n) = 2 + 7*(n mod 2) = 2 + 7*A000035(n). - _M. F. Hasler_, Feb 26 2020
%t A010699 PadRight[{},100,{2,9}] (* _Harvey P. Dale_, Mar 25 2015 *)
%o A010699 (PARI) a(n)=n%2*7+2 \\ _Charles R Greathouse IV_, Jul 13 2016
%Y A010699 Equals 2 + A010678 = 2 + 7*A000035.
%K A010699 nonn,easy
%O A010699 0,1
%A A010699 _N. J. A. Sloane_