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 A010714 #30 Dec 31 2023 16:08:00
%S A010714 4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,
%T A010714 4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,4,9,
%U A010714 4,9,4,9,4,9,4,9,4,9,4,9,4
%N A010714 Period 2: repeat [4, 9].
%H A010714 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010714 G.f.: (4+9x)/((1-x)*(1+x)). - _R. J. Mathar_, Nov 21 2011
%F A010714 From _Wesley Ivan Hurt_, Dec 31 2023: (Start)
%F A010714 a(n) = a(n-2) for n>1 with a(0)=4, a(1)=9.
%F A010714 a(n) = (13-5*(-1)^n)/2. (End)
%t A010714 Table[4 + 5 Mod[n, 2], {n, 0, 50}] (* _Jinyuan Wang_, Feb 26 2020 *)
%o A010714 (PARI) a(n)=4+n%2*5 \\ _Charles R Greathouse IV_, Dec 21 2011
%Y A010714 Cf. A176219.
%K A010714 nonn,easy
%O A010714 0,1
%A A010714 _N. J. A. Sloane_