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 A198966 #17 Sep 08 2022 08:46:00
%S A198966 7,71,647,5831,52487,472391,4251527,38263751,344373767,3099363911,
%T A198966 27894275207,251048476871,2259436291847,20334926626631,
%U A198966 183014339639687,1647129056757191,14824161510814727,133417453597332551,1200757082375992967
%N A198966 a(n) = 8*9^n-1.
%H A198966 Vincenzo Librandi, <a href="/A198966/b198966.txt">Table of n, a(n) for n = 0..1000</a>
%H A198966 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10,-9).
%F A198966 a(n) = 9*a(n-1)+8. a(n) = 10*a(n-1)-9*a(n-2), n>1.
%F A198966 G.f.: (7 + x)/(1 - 10*x + 9*x^2). - _Vincenzo Librandi_, Jan 03 2013
%t A198966 CoefficientList[Series[(7 + x)/(1 - 10*x + 9*x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 03 2013 *)
%o A198966 (Magma) [8*9^n-1: n in [0..20]]
%o A198966 (PARI) a(n) = 8*9^n - 1; \\ _Michel Marcus_, Feb 03 2016
%K A198966 nonn,easy
%O A198966 0,1
%A A198966 _Vincenzo Librandi_, Nov 01 2011