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 A156198 #17 Sep 08 2022 08:45:41
%S A156198 8,19,41,85,173,349,701,1405,2813,5629,11261,22525,45053,90109,180221,
%T A156198 360445,720893,1441789,2883581,5767165,11534333,23068669,46137341,
%U A156198 92274685,184549373,369098749,738197501,1476395005,2952790013
%N A156198 a(n) = 2*a(n-1)+3 with n>1, a(1)=8.
%H A156198 Vincenzo Librandi, <a href="/A156198/b156198.txt">Table of n, a(n) for n = 1..1000</a>
%H A156198 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).
%F A156198 G.f.: (8*x-5*x^2)/(1-3*x+2*x^2). [_Philippe Deléham_, Feb 09 2009]
%F A156198 a(n) = 3*a(n-1)-2*a(n-2) = 11*2^(n-1)-3. [_R. J. Mathar_, Feb 19 2009]
%t A156198 LinearRecurrence[{3,-2},{8,19},30] (* _Vincenzo Librandi_, May 02 2012 *)
%t A156198 NestList[2#+3&,8,30] (* _Harvey P. Dale_, Oct 17 2016 *)
%o A156198 (Magma) I:=[8, 19]; [n le 2 select I[n] else 3*Self(n-1)-2*Self(n-2): n in [1..30]]; // _Librandi Vincenzo_, May 02 2012
%K A156198 nonn,easy
%O A156198 1,1
%A A156198 _Vincenzo Librandi_, Feb 08 2009