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 A199416 #11 Sep 08 2022 08:46:00 %S A199416 3,15,99,687,4803,33615,235299,1647087,11529603,80707215,564950499, %T A199416 3954653487,27682574403,193778020815,1356446145699,9495123019887, %U A199416 66465861139203,465261027974415,3256827195820899,22797790370746287 %N A199416 2*7^n+1. %H A199416 Vincenzo Librandi, <a href="/A199416/b199416.txt">Table of n, a(n) for n = 0..1000</a> %H A199416 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,-7). %F A199416 a(n) = 3*A083076(n). %F A199416 a(n) = 7*a(n-1)-6. %F A199416 a(n) = 8*a(n-1)-7*a(n-2). %F A199416 G.f.: 3*(1-3*x)/((1-x)*(1-7*x)). %o A199416 (Magma) [2*7^n+1: n in [0..30]]; %K A199416 nonn,easy %O A199416 0,1 %A A199416 _Vincenzo Librandi_, Nov 06 2011