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%I #21 Sep 08 2022 08:46:00
%S 3,31,283,2551,22963,206671,1860043,16740391,150663523,1355971711,
%T 12203745403,109833708631,988503377683,8896530399151,80068773592363,
%U 720618962331271,6485570660981443,58370135948832991,525331223539496923
%N (7*9^n-1)/2.
%H Vincenzo Librandi, <a href="/A198964/b198964.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)+4.
%F a(n) = 10*a(n-1)-9*a(n-2), n>1.
%F G.f.: (3 + x)/(1 - 10*x + 9*x^2). - _Vincenzo Librandi_, Jan 03 2013
%t CoefficientList[Series[(3 + x)/(1 - 10 x + 9 x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 03 2013 *)
%t LinearRecurrence[{10,-9},{3,31},30] (* _Harvey P. Dale_, Oct 10 2017 *)
%o (Magma) [(7*9^n-1)/2: n in [0..20]];
%o (PARI) a(n)=7*9^n\2 \\ _Charles R Greathouse IV_, Oct 16 2015
%K nonn,easy
%O 0,1
%A _Vincenzo Librandi_, Nov 01 2011
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