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 A010697 #59 Jul 08 2025 01:44:38
%S A010697 2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,
%T A010697 2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,2,7,
%U A010697 2,7,2,7,2,7,2,7,2,7,2,7,2
%N A010697 Period 2: repeat (2,7).
%C A010697 Continued fraction expansion of A176054. - _R. J. Mathar_, Mar 08 2012
%C A010697 Decimal expansion of 3/11. - _Franklin T. Adams-Watters_, Nov 21 2018
%H A010697 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F A010697 G.f.: (2+7x)/((1-x)(1+x)). - _R. J. Mathar_, Nov 21 2011
%F A010697 a(n) = A010888(2^n+5^n) = A010888(A074600(n)). - _Peter M. Chema_, Jul 13 2016
%F A010697 E.g.f.: 7*sinh(x) + 2*cosh(x). - _Ilya Gutkovskiy_, Jul 14 2016
%F A010697 a(n) = 14/a(n-1). - _Nicolas Bělohoubek_, Nov 11 2021
%t A010697 Table[-5/2*(-1)^n + 9/2, {n, 0, 120}] (* or *)
%t A010697 Table[7 Mod[n, 2] + 2 Mod[(n + 1), 2], {n, 0, 120}] (* or *)
%t A010697 CoefficientList[Series[(2 + 7 x)/((1 - x) (1 + x)), {x, 0, 120}], x] (* or *)
%t A010697 Table[NestWhile[Total@ IntegerDigits@ # &, 2^n + 5^n, IntegerLength@ # > 1 &], {n, 0, 120}] (* _Michael De Vlieger_, Jul 13 2016 *)
%o A010697 (PARI) a(n)=if(n%2,7,2) \\ _Charles R Greathouse IV_, Oct 07 2015
%Y A010697 Cf. A010888, A074600.
%K A010697 nonn,easy
%O A010697 0,1
%A A010697 _N. J. A. Sloane_