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 A190982 #29 Dec 23 2023 09:45:27
%S A190982 0,1,9,76,639,5371,45144,379441,3189249,26806036,225308079,1893742531,
%T A190982 15917142384,133785568801,1124484407289,9451431821596,79440464357919,
%U A190982 667707020113291,5612160859230024,47170912632503761,396477409396383729,3332442121404934756
%N A190982 a(n) = 9*a(n-1) - 5*a(n-2), with a(0)=0, a(1)=1.
%H A190982 G. C. Greubel, <a href="/A190982/b190982.txt">Table of n, a(n) for n = 0..1000</a>
%H A190982 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (9,-5).
%F A190982 G.f.: x/(1 - 9*x + 5*x^2). - _Philippe Deléham_, Oct 12 2011
%F A190982 E.g.f.: (2/sqrt(61))*exp(9*x/2)*sinh(sqrt(61)*x/2). - _G. C. Greubel_, Aug 26 2022
%t A190982 LinearRecurrence[{9,-5}, {0,1}, 50]
%o A190982 (Magma) [Round(5^((n-1)/2)*Evaluate(ChebyshevU(n), 9/(2*Sqrt(5)))): n in [0..30]]; // _G. C. Greubel_, Aug 26 2022
%o A190982 (SageMath)
%o A190982 A190982 = BinaryRecurrenceSequence(9,-5,0,1)
%o A190982 [A190982(n) for n in (0..30)] # _G. C. Greubel_, Aug 26 2022
%Y A190982 Cf. A190958 (index to generalized Fibonacci sequences).
%K A190982 nonn
%O A190982 0,3
%A A190982 _Vladimir Joseph Stephan Orlovsky_, May 24 2011