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 A014943 #16 May 21 2025 01:35:15
%S A014943 1,51,1926,64426,2017551,60611301,1769595676,50597720676,
%T A014943 1423888736301,39570861392551,1088612609439426,29698842101626926,
%U A014943 804559224181705051,21666184895568423801,580459729664855533176,15481620923512511783176,411293715135090880923801,10888672679559224181705051
%N A014943 a(1)=1, a(n) = n*25^(n-1) + a(n-1).
%H A014943 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (51,-675,625).
%F A014943 a(n) = 51*a(n-1) - 675*a(n-2) + 625*a(n-3), a(1)=1, a(2)=51, a(3)=1926. - _Harvey P. Dale_, Dec 16 2012
%F A014943 From _Elmo R. Oliveira_, May 18 2025: (Start)
%F A014943 G.f.: -x/((x-1)*(25*x-1)^2).
%F A014943 E.g.f.: exp(x)*(1 + exp(24*x)*(600*x - 1))/576.
%F A014943 a(n) = (26^n*(25*n - 1) + 1)/576.
%F A014943 a(n) = 50*a(n-1) - 625*a(n-2) + 1 for n > 2. (End)
%t A014943 RecurrenceTable[{a[1]==1,a[n]==n*25^(n-1)+a[n-1]},a,{n,20}] (* or *)
%t A014943 LinearRecurrence[{51,-675,625},{1,51,1926},20] (* _Harvey P. Dale_, Dec 16 2012 *)
%o A014943 (PARI) Vec(x/((1-x)*(1-25*x)^2) + O(x^19)) \\ _Elmo R. Oliveira_, May 18 2025
%K A014943 nonn,easy
%O A014943 1,2
%A A014943 _Olivier Gérard_
%E A014943 More terms from _Elmo R. Oliveira_, May 18 2025