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 A199112 #22 Mar 20 2023 05:08:18
%S A199112 11,31,91,271,811,2431,7291,21871,65611,196831,590491,1771471,5314411,
%T A199112 15943231,47829691,143489071,430467211,1291401631,3874204891,
%U A199112 11622614671,34867844011,104603532031,313810596091,941431788271,2824295364811
%N A199112 a(n) = 10*3^n+1.
%C A199112 The inverse binomial transform is 11, 20, 40, 80, 160,... closely related to A020714. - _R. J. Mathar_, Apr 07 2022
%H A199112 Vincenzo Librandi, <a href="/A199112/b199112.txt">Table of n, a(n) for n = 0..1000</a>
%H A199112 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (4,-3).
%F A199112 a(n) = 3*a(n-1)-2.
%F A199112 a(n) = 4*a(n-1)-3*a(n-2).
%F A199112 G.f.: (11-13*x)/((1-x)*(1-3*x)). - _Bruno Berselli_, Nov 04 2011
%t A199112 10*3^Range[0,30]+1 (* or *) LinearRecurrence[{4,-3},{11,31},30] (* _Harvey P. Dale_, Dec 07 2011 *)
%o A199112 (Magma) [10*3^n+1: n in [0..30]];
%Y A199112 Cf. A020714.
%K A199112 nonn,easy
%O A199112 0,1
%A A199112 _Vincenzo Librandi_, Nov 04 2011