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 A014937 #19 May 18 2025 07:56:47
%S A014937 1,41,1241,33241,833241,20033241,468033241,10708033241,241108033241,
%T A014937 5361108033241,118001108033241,2575601108033241,55823601108033241,
%U A014937 1202703601108033241,25778703601108033241,550066703601108033241,11691186703601108033241,247620786703601108033241
%N A014937 a(1)=1, a(n) = n*20^(n-1) + a(n-1).
%H A014937 Harvey P. Dale, <a href="/A014937/b014937.txt">Table of n, a(n) for n = 1..750</a>
%H A014937 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (41,-440,400).
%F A014937 a(n) = 41*a(n-1) - 440*a(n-2) + 400*a(n-3), a(1)=1, a(2)=41, a(3)=1241. - _Harvey P. Dale_, Jun 04 2012
%F A014937 G.f.: -x/((x-1)*(-1+20*x)^2). - _R. J. Mathar_, Nov 07 2015
%F A014937 From _Elmo R. Oliveira_, May 16 2025: (Start)
%F A014937 E.g.f.: exp(x)*(1 + exp(19*x)*(380*x - 1))/361.
%F A014937 a(n) = (20^n*(19*n - 1) + 1)/361.
%F A014937 a(n) = 40*a(n-1) - 400*a(n-2) + 1 for n > 2. (End)
%t A014937 RecurrenceTable[{a[1]==1,a[n]==n*20^(n-1)+a[n-1]},a,{n,20}] (* or *) LinearRecurrence[{41,-440,400},{1,41,1241},20] (* _Harvey P. Dale_, Jun 04 2012 *)
%K A014937 nonn,easy
%O A014937 1,2
%A A014937 _Olivier Gérard_