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 A159289 #22 Mar 08 2024 11:57:58
%S A159289 5,21,95,433,1975,9009,41095,187457,855095,3900561,17792615,81161953,
%T A159289 370224535,1688798769,7703544775,35140126337,160293542135,
%U A159289 731187458001,3335350205735,15214376112673,69401180151895,316577148534129
%N A159289 a(n+1) = 5*a(n) - 2*a(n-1).
%H A159289 G. C. Greubel, <a href="/A159289/b159289.txt">Table of n, a(n) for n = 0..1000</a>
%H A159289 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (5, -2).
%F A159289 From _R. J. Mathar_, Apr 10 2009: (Start)
%F A159289 G.f.: -(-5+4*x)/(1-5*x+2*x^2).
%F A159289 a(n) = 5*A107839(n) - 4*A107839(n-1). (End)
%t A159289 LinearRecurrence[{5, -2}, {5, 21}, 50] (* _G. C. Greubel_, Jun 27 2018 *)
%o A159289 (PARI) x='x+O('x^30); Vec(-(-5+4*x)/(1-5*x+2*x^2)) \\ _G. C. Greubel_, Jun 27 2018
%o A159289 (Magma) I:=[5, 21]; [n le 2 select I[n] else 5*Self(n-1) - 2*Self(n-2): n in [1..30]]; // _G. C. Greubel_, Jun 27 2018
%Y A159289 Cf. A107839.
%K A159289 nonn,easy
%O A159289 0,1
%A A159289 _Creighton Dement_, Apr 08 2009