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 A206609 #19 Jun 05 2024 12:09:16
%S A206609 13,9,22,31,53,84,137,221,358,579,937,1516,2453,3969,6422,10391,16813,
%T A206609 27204,44017,71221,115238,186459,301697,488156,789853,1278009,2067862,
%U A206609 3345871,5413733,8759604,14173337,22932941,37106278,60039219,97145497,157184716
%N A206609 Fibonacci sequence beginning 13, 9.
%H A206609 Vincenzo Librandi, <a href="/A206609/b206609.txt">Table of n, a(n) for n = 1..1000</a>
%H A206609 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1, 1).
%t A206609 LinearRecurrence[{1, 1}, {13, 9}, 80]
%o A206609 (Magma) I:=[13, 9]; [n le 2 select I[n] else Self(n-1)+Self(n-2): n in [1..40]]; // _Vincenzo Librandi_, Feb 16 2012
%Y A206609 Cf. A000032, A000045, A206607, A206608.
%K A206609 nonn,easy
%O A206609 1,1
%A A206609 _Vladimir Joseph Stephan Orlovsky_, Feb 10 2012