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 A198399 #26 Sep 10 2024 08:45:21
%S A198399 1,0,63,702,6525,59004,531387,4782906,43046649,387420408,3486784311,
%T A198399 31381059510,282429536373,2541865828212,22876792454835,
%U A198399 205891132094514,1853020188851697,16677181699666416,150094635296998959,1350851717672991918,12157665459056928621,109418989131512359020
%N A198399 a(n) = 9^n - 9*n.
%H A198399 Vincenzo Librandi, <a href="/A198399/b198399.txt">Table of n, a(n) for n = 0..1000</a>
%H A198399 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (11,-19,9).
%F A198399 a(0)=1, a(1)=0, a(2)=63, a(n) = 11*a(n-1) - 19*a(n-2) + 9*a(n-3).
%F A198399 G.f.: (1 - 11*x + 82*x^2)/((1 - 9*x)*(1 - x)^2). - _Vincenzo Librandi_, Jan 04 2013
%F A198399 E.g.f.: exp(x)*(exp(8*x) - 9*x). - _Elmo R. Oliveira_, Sep 09 2024
%t A198399 CoefficientList[Series[(1 - 11*x + 82*x^2)/((1 - 9*x)*(1 - x)^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 04 2013 *)
%o A198399 (Magma) [9^n-9*n: n in [0..25]];
%o A198399 (PARI) a(n)=9^n-9*n \\ _Charles R Greathouse IV_, Jul 06 2017
%Y A198399 Cf. A005803, A107583, A107584, A107585.
%K A198399 nonn,easy
%O A198399 0,3
%A A198399 _Vincenzo Librandi_, Oct 26 2011