%I #12 Sep 08 2022 08:45:50
%S 1,12,104,1006,10008,100010,1000012,10000014,100000016,1000000018,
%T 10000000020,100000000022,1000000000024,10000000000026,
%U 100000000000028,1000000000000030,10000000000000032,100000000000000034
%N 10^n+2*n.
%H Vincenzo Librandi, <a href="/A173835/b173835.txt">Table of n, a(n) for n = 0..100</a>
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (12,-21,10).
%F G.f.: (1-19*x^2)/((1-x)^2*(1-10*x)). - _Vincenzo Librandi_, Jul 06 2012
%F a(n) = 11*a(n-1) -10*a(n-2) -18. - _Vincenzo Librandi_, Jul 06 2012
%t CoefficientList[Series[(1-19*x^2)/((1-x)^2*(1-10*x)),{x,0,40}],x] (* _Vincenzo Librandi_, Jul 06 2012 *)
%t LinearRecurrence[{12,-21,10},{1,12,104},20] (* _Harvey P. Dale_, Dec 01 2015 *)
%o (Magma) I:=[1, 12]; [n le 2 select I[n] else 11*Self(n-1)-10*Self(n-2)-18: n in [1..20]]; // _Vincenzo Librandi_, Jul 06 2012
%K nonn,easy
%O 0,2
%A _Vincenzo Librandi_, Feb 26 2010