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 A190510 #36 Jan 03 2024 08:51:35
%S A190510 0,1,8,68,576,4880,41344,350272,2967552,25141504,213002240,1804583936,
%T A190510 15288680448,129527779328,1097376956416,9297126768640,78766521974784,
%U A190510 667320682872832,5653631550881792,47898335138545664,405801207311892480,3438002999049322496
%N A190510 a(n) = 8*a(n-1) + 4*a(n-2), with a(0)=0, a(1)=1.
%H A190510 Vincenzo Librandi, <a href="/A190510/b190510.txt">Table of n, a(n) for n = 0..1000</a>
%H A190510 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,4).
%F A190510 G.f.: x/(1 - 8*x - 4*x^2). - _R. J. Mathar_, Nov 21 2011
%F A190510 a(n+1) = Sum_{k, 0<=k<=n} A099089(n,k)*4^k. - _Philippe Deléham_, Nov 21 2011
%t A190510 LinearRecurrence[{8,4}, {0,1}, 50]
%o A190510 (Magma) I:=[0, 1]; [n le 2 select I[n] else 8*Self(n-1)+4*Self(n-2): n in [1..20]]; // _Vincenzo Librandi_, Nov 23 2011
%o A190510 (PARI) x='x+O('x^30); concat([0], Vec(x/(1-8*x-4*x^2))) \\ _G. C. Greubel_, Jan 24 2018
%K A190510 nonn,easy
%O A190510 0,3
%A A190510 _Vladimir Joseph Stephan Orlovsky_, May 24 2011