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11*9^n-1.
1

%I #16 Sep 08 2022 08:46:00

%S 10,98,890,8018,72170,649538,5845850,52612658,473513930,4261625378,

%T 38354628410,345191655698,3106724901290,27960524111618,

%U 251644717004570,2264802453041138,20383222077370250,183448998696332258,1651040988266990330

%N 11*9^n-1.

%H Vincenzo Librandi, <a href="/A198968/b198968.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (10,-9).

%F a(n) = 9*a(n-1)+8. a(n) = 10*a(n-1)-9*a(n-2), n>1.

%F G.f.: 2*(5 - x)/(1 - 10*x + 9*x^2). - _Vincenzo Librandi_, Jan 03 2013

%t CoefficientList[Series[2*(5 - x)/(1 - 10*x + 9*x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 03 2013 *)

%t LinearRecurrence[{10,-9},{10,98},30] (* _Harvey P. Dale_, Jun 26 2013 *)

%o (Magma) [11*9^n-1: n in [0..20]]

%K nonn,easy

%O 0,1

%A _Vincenzo Librandi_, Nov 01 2011