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 A198962 #17 Sep 08 2022 08:46:00
%S A198962 4,44,404,3644,32804,295244,2657204,23914844,215233604,1937102444,
%T A198962 17433922004,156905298044,1412147682404,12709329141644,
%U A198962 114383962274804,1029455660473244,9265100944259204,83385908498332844,750473176484995604
%N A198962 5*9^n-1.
%H A198962 Vincenzo Librandi, <a href="/A198962/b198962.txt">Table of n, a(n) for n = 0..1000</a>
%H A198962 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (10,-9).
%F A198962 a(n) = 4*A138894(n).
%F A198962 a(n) = 9*a(n-1)+8, n>0.
%F A198962 a(n) = 10*a(n-1)-9*a(n-2), n>1.
%F A198962 G.f. ( 4+4*x ) / ( (9*x-1)*(x-1) ). - R. J. Mathar, Nov 01 2011
%t A198962 5*9^Range[0,30]-1 (* or *) LinearRecurrence[{10,-9},{4,44},30] (* _Harvey P. Dale_, Oct 20 2019 *)
%o A198962 (Magma) [5*9^n-1: n in [0..20]]
%K A198962 nonn,easy
%O A198962 0,1
%A A198962 _Vincenzo Librandi_, Nov 01 2011