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 A199214 #18 Mar 20 2023 11:52:01
%S A199214 4,16,76,376,1876,9376,46876,234376,1171876,5859376,29296876,
%T A199214 146484376,732421876,3662109376,18310546876,91552734376,457763671876,
%U A199214 2288818359376,11444091796876,57220458984376,286102294921876,1430511474609376
%N A199214 a(n) = 3*5^n+1.
%H A199214 Vincenzo Librandi, <a href="/A199214/b199214.txt">Table of n, a(n) for n = 0..1000</a>
%H A199214 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-5).
%F A199214 a(n) = 4*A083065(n).
%F A199214 a(n) = 5*a(n-1)-4.
%F A199214 a(n) = 6*a(n-1)-5*a(n-2).
%F A199214 G.f.: 4*(1-2*x)/((1-x)*(1-5*x)). - _Bruno Berselli_, Nov 04 2011
%t A199214 LinearRecurrence[{6,-5},{4,16},30] (* _Harvey P. Dale_, Jul 08 2013 *)
%o A199214 (Magma) [3*5^n+1: n in [0..30]];
%Y A199214 Cf. A083065.
%K A199214 nonn,easy
%O A199214 0,1
%A A199214 _Vincenzo Librandi_, Nov 04 2011