A198966 - OEIS

%I #17 Sep 08 2022 08:46:00

%S 7,71,647,5831,52487,472391,4251527,38263751,344373767,3099363911,

%T 27894275207,251048476871,2259436291847,20334926626631,

%U 183014339639687,1647129056757191,14824161510814727,133417453597332551,1200757082375992967

%N a(n) = 8*9^n-1.

%H Vincenzo Librandi, <a href="/A198966/b198966.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_02">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.: (7 + x)/(1 - 10*x + 9*x^2). - _Vincenzo Librandi_, Jan 03 2013

%t CoefficientList[Series[(7 + x)/(1 - 10*x + 9*x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 03 2013 *)

%o (Magma) [8*9^n-1: n in [0..20]]

%o (PARI) a(n) = 8*9^n - 1; \\ _Michel Marcus_, Feb 03 2016

%K nonn,easy

%O 0,1

%A _Vincenzo Librandi_, Nov 01 2011