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 A014881 #42 Mar 31 2025 13:38:31
%S A014881 1,13,146,1610,17715,194871,2143588,23579476,259374245,2853116705,
%T A014881 31384283766,345227121438,3797498335831,41772481694155,
%U A014881 459497298635720,5054470284992936,55599173134922313,611590904484145461,6727499949325600090,74002499442581601010
%N A014881 a(1)=1, a(n) = 11*a(n-1) + n.
%H A014881 Vincenzo Librandi, <a href="/A014881/b014881.txt">Table of n, a(n) for n = 1..200</a>
%H A014881 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (13,-23,11).
%F A014881 a(n) = 13*a(n-1) - 23*a(n-2) + 11*a(n-3), with a(1)=1, a(2)=13, a(3)=146. - _Vincenzo Librandi_, Oct 20 2012
%F A014881 G.f.: x/((1-11*x)*(1-x)^2). - _Jinyuan Wang_, Mar 11 2020
%F A014881 From _Elmo R. Oliveira_, Mar 31 2025: (Start)
%F A014881 E.g.f.: exp(x)*(11*exp(10*x) - 10*x - 11)/100.
%F A014881 a(n) = (11^(n+1) - 10*n - 11)/100. (End)
%p A014881 a:= n-> (Matrix([[1,0,1],[1,1,1],[0,0,11]])^n)[2,3]:
%p A014881 seq(a(n), n=1..17); # _Alois P. Heinz_, Aug 06 2008
%t A014881 LinearRecurrence[{13, -23, 11}, {1, 13, 146}, 20] (* _Vincenzo Librandi_, Oct 20 2012 *)
%o A014881 (Magma) I:=[1, 13, 146]; [n le 3 select I[n] else 13*Self(n-1) - 23*Self(n-2)+ 11*Self(n-3): n in [1..20]]; // _Vincenzo Librandi_, Oct 20 2012
%Y A014881 Row n=11 of A126885.
%K A014881 nonn,easy
%O A014881 1,2
%A A014881 _N. J. A. Sloane_, _Olivier Gérard_