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 A196512 #35 Mar 25 2025 19:19:54
%S A196512 1,19,532,14896,417088,11678464,326996992,9155915776,256365641728,
%T A196512 7178237968384,200990663114752,5627738567213056,157576679881965568,
%U A196512 4412147036695035904,123540117027461005312,3459123276768908148736,96855451749529428164608,2711952648986823988609024
%N A196512 Expansion of g.f. (1-9*x)/(1-28*x).
%H A196512 Vincenzo Librandi, <a href="/A196512/b196512.txt">Table of n, a(n) for n = 0..500</a>
%H A196512 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (28).
%F A196512 a(n) = 19*28^(n-1) for n > 0, a(0)=1.
%F A196512 a(n) = Sum_{k=0..n} A193722(n,k)*9^k.
%F A196512 From _Elmo R. Oliveira_, Mar 25 2025: (Start)
%F A196512 E.g.f.: (19*exp(28*x) + 9)/28.
%F A196512 a(n) = 28*a(n-1) for n > 1. (End)
%t A196512 Join[{1},19*28^Range[0,20]] (* _Harvey P. Dale_, Dec 06 2015 *)
%o A196512 (PARI) a(n)=if(n,19*28^(n-1),1) \\ _M. F. Hasler_, Oct 06 2011
%o A196512 (Magma) [1] cat [19*28^(n-1) : n in [1..15]]; // _Vincenzo Librandi_, Oct 06 2011
%Y A196512 Cf. A002001, A193722, A196661, A196662, A196663, A196664, A196665, A196666, A196676.
%K A196512 nonn,easy
%O A196512 0,2
%A A196512 _Philippe Deléham_, Oct 05 2011