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 A010707 #26 Jul 08 2025 01:44:47
%S A010707 3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,
%T A010707 3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,3,9,
%U A010707 3,9,3,9,3,9,3,9,3,9,3,9,3
%N A010707 Period 2: repeat (3,9).
%C A010707 Continued fraction expansion of A176108. - _R. J. Mathar_, Mar 08 2012
%H A010707 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010707 a(n) = -3*(-1)^n+6. - _Paolo P. Lava_, Oct 20 2006
%F A010707 G.f.: 3(1+3x)/((1-x)(1+x)). - _R. J. Mathar_, Nov 21 2011
%t A010707 PadRight[{},120,{3,9}] (* _Harvey P. Dale_, Nov 07 2017 *)
%o A010707 (PARI) a(n)=3+n%2*6 \\ _Charles R Greathouse IV_, Dec 21 2011
%K A010707 nonn,easy
%O A010707 0,1
%A A010707 _N. J. A. Sloane_