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 A086594 #35 Sep 08 2022 08:45:11
%S A086594 2,8,66,536,4354,35368,287298,2333752,18957314,153992264,1250895426,
%T A086594 10161155672,82540140802,670482282088,5446398397506,44241669462136,
%U A086594 359379754094594,2919279702218888,23713617371845698,192628218676984472,1564739366787721474
%N A086594 a(n) = 8*a(n-1) + a(n-2), starting with a(0)=2 and a(1)=8.
%C A086594 a(n+1)/a(n) converges to 4 + sqrt(17).
%H A086594 Vincenzo Librandi, <a href="/A086594/b086594.txt">Table of n, a(n) for n = 0..1000</a>
%H A086594 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A086594 <a href="/index/Rea#recur1">Index entries for recurrences a(n) = k*a(n - 1) +/- a(n - 2)</a>
%H A086594 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,1).
%F A086594 a(n) = (4+sqrt(17))^n + (4-sqrt(17))^n.
%F A086594 O.g.f: 2*(-1+4*x)/(-1+8*x+x^2). - _R. J. Mathar_, Dec 02 2007
%F A086594 a(n) = 2*A088317(n). - _R. J. Mathar_, Sep 27 2014
%e A086594 a(4) = 8*a(3)+a(2) = 8*536+66 = 4354.
%t A086594 LinearRecurrence[{8,1},{2,8},30] (* _Harvey P. Dale_, Sep 21 2014 *)
%t A086594 RecurrenceTable[{a[0] == 2, a[1] == 8, a[n] == 8 a[n-1] + a[n-2]}, a, {n, 30}] (* _Vincenzo Librandi_, Sep 19 2016 *)
%o A086594 (Magma) I:=[2,8]; [n le 2 select I[n] else 8*Self(n-1)+Self(n-2): n in [1..30]]; // _Vincenzo Librandi_, Sep 19 2016
%o A086594 (PARI) x='x+O('x^30); Vec(2*(1-4*x)/(1-8*x-x^2)) \\ _G. C. Greubel_, Nov 07 2018
%Y A086594 Cf. A003285.
%K A086594 nonn,easy
%O A086594 0,1
%A A086594 Nikolay V. Kosinov (kosinov(AT)unitron.com.ua), Sep 11 2003