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 A010713 #26 Dec 14 2023 06:04:33
%S A010713 4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,
%T A010713 4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,4,8,
%U A010713 4,8,4,8,4,8,4,8,4,8,4,8,4
%N A010713 Period 2: repeat (4,8).
%H A010713 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010713 a(n) = -2*(-1)^n + 6. - _Paolo P. Lava_, Oct 20 2006
%F A010713 From _R. J. Mathar_, Oct 20 2008: (Start)
%F A010713 a(n) = 4*A000034(n).
%F A010713 G.f.: 4(1+2x)/((1-x)(1+x)). (End)
%t A010713 Table[4 + 4 Mod[n, 2], {n, 0, 50}] (* _Jinyuan Wang_, Feb 26 2020 *)
%t A010713 LinearRecurrence[{0,1},{4,8},100] (* or *) PadRight[{},100,{4,8}] (* _Harvey P. Dale_, Aug 29 2023 *)
%o A010713 (PARI) a(n)=4+n%2*4 \\ _Charles R Greathouse IV_, Dec 21 2011
%Y A010713 Cf. A176218.
%K A010713 nonn,easy
%O A010713 0,1
%A A010713 _N. J. A. Sloane_