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 A141012 #26 Nov 13 2018 03:11:17
%S A141012 0,2,14,170,2198,28562,371294,4826810,62748518,815730722,10604499374,
%T A141012 137858491850,1792160394038,23298085122482,302875106592254,
%U A141012 3937376385699290,51185893014090758
%N A141012 a(0) = 0, a(n) = 13^(n-1) + 1.
%H A141012 Vincenzo Librandi, <a href="/A141012/b141012.txt">Table of n, a(n) for n = 0..900</a>
%H A141012 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (14, -13).
%F A141012 E.g.f.: Sum_{d|M} (exp(d*x) - 1)/d, M=13.
%F A141012 From _R. J. Mathar_, Mar 05 2010: (Start)
%F A141012 a(n) = Sum_{d|13} d^(n-1) = 1 + 13^(n-1) = 1 + A001022(n-1), n > 0.
%F A141012 a(n) = 14*a(n-1) - 13*a(n-2), n > 2.
%F A141012 G.f.: -2*x*(-1+7*x)/((13*x-1)*(x-1)). (End)
%F A141012 a(n) = 13*a(n-1) - 12, n > 1. - _Vincenzo Librandi_, Sep 17 2011
%t A141012 Join[{0},13^(#-1)+1&/@Range[20]] (* or *) Join[{0},LinearRecurrence[ {14,-13},{2,14},20]] (* _Harvey P. Dale_, Oct 14 2013 *)
%K A141012 nonn,easy
%O A141012 0,2
%A A141012 _R. J. Mathar_, Jul 11 2008
%E A141012 Name changed by _Arkadiusz Wesolowski_, Sep 08 2013