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 A198769 #17 Sep 01 2025 16:54:13
%S A198769 2,11,56,281,1406,7031,35156,175781,878906,4394531,21972656,109863281,
%T A198769 549316406,2746582031,13732910156,68664550781,343322753906,
%U A198769 1716613769531,8583068847656,42915344238281,214576721191406,1072883605957031,5364418029785156,26822090148925781
%N A198769 a(n) = (9*5^n-1)/4.
%H A198769 Vincenzo Librandi, <a href="/A198769/b198769.txt">Table of n, a(n) for n = 0..1000</a>
%H A198769 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-5).
%F A198769 a(n) = 5*a(n-1)+1.
%F A198769 a(n) = 6*a(n-1)-5*a(n-2), n>1.
%F A198769 G.f.: (2-x)/(5*x^2-6*x+1). - _Harvey P. Dale_, May 07 2012
%t A198769 (9*5^Range[0,30]-1)/4 (* or *) LinearRecurrence[{6,-5},{2,11},30] (* _Harvey P. Dale_, May 07 2012 *)
%o A198769 (Magma) [(9*5^n-1)/4: n in [0..30]];
%Y A198769 Cf. A024049, A057651, A081655.
%K A198769 nonn,easy,changed
%O A198769 0,1
%A A198769 _Vincenzo Librandi_, Oct 30 2011