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 A198770 #18 Sep 08 2022 08:46:00
%S A198770 10,54,274,1374,6874,34374,171874,859374,4296874,21484374,107421874,
%T A198770 537109374,2685546874,13427734374,67138671874,335693359374,
%U A198770 1678466796874,8392333984374,41961669921874,209808349609374,1049041748046874
%N A198770 11*5^n-1.
%H A198770 Vincenzo Librandi, <a href="/A198770/b198770.txt">Table of n, a(n) for n = 0..1000</a>
%H A198770 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (6,-5).
%F A198770 a(n) = 5*a(n-1)+4.
%F A198770 a(n)= = 6*a(n-1)-5*a(n-2), n>1.
%F A198770 G.f.: 2*(5 - 3*x)/(1 - 6*x + 5*x^2). - _Vincenzo Librandi_, Jan 04 2013
%t A198770 CoefficientList[Series[2*(5 - 3*x)/(1 - 6*x + 5*x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 04 2013 *)
%t A198770 11*5^Range[0,20]-1 (* or *) LinearRecurrence[{6,-5},{10,54},30] (* _Harvey P. Dale_, May 14 2019 *)
%o A198770 (Magma) [11*5^n-1: n in [0..30]];
%Y A198770 Cf. A024049, A057651, A081655.
%K A198770 nonn,easy
%O A198770 0,1
%A A198770 _Vincenzo Librandi_, Oct 30 2011