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a(n) = 3*10^n-1.
1

%I #18 Sep 13 2024 15:47:42

%S 2,29,299,2999,29999,299999,2999999,29999999,299999999,2999999999,

%T 29999999999,299999999999,2999999999999,29999999999999,

%U 299999999999999,2999999999999999,29999999999999999,299999999999999999

%N a(n) = 3*10^n-1.

%H Vincenzo Librandi, <a href="/A198698/b198698.txt">Table of n, a(n) for n = 0..200</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10).

%F a(n) = 10*a(n-1)+9, a(0)=2. a(n) = 11*a(n-1)-10*a(n-2), n>1.

%F G.f.: ( 2+7*x ) / ( (10*x-1)*(x-1) ). - _R. J. Mathar_, Oct 30 2011

%o (Magma) [3*10^n-1: n in [0..30]];

%Y Cf. A002283, A109002.

%K nonn,easy

%O 0,1

%A _Vincenzo Librandi_, Oct 29 2011