%I #19 Jun 30 2023 14:20:55
%S 9,19,119,1119,11119,111119,1111119,11111119,111111119,1111111119,
%T 11111111119,111111111119,1111111111119,11111111111119,
%U 111111111111119,1111111111111119,11111111111111119
%N a(n) = (10^n + 71)/9.
%C Also n - 1 ones followed by a nine.
%H Vincenzo Librandi, <a href="/A165247/b165247.txt">Table of n, a(n) for n = 1..100</a>
%H Markus Tervooren, <a href="http://factordb.com/search.php?query=%2810%5Ex%2B71%29%2F9">Factorizations of (1)w9</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11, -10).
%F G.f.: x*(9 - 80*x)/((1 - x)*(1 - 10*x)). - _Vincenzo Librandi_, Apr 26 2014
%t Table[FromDigits[PadLeft[{9}, n, 1]], {n, 20}] (* _Harvey P. Dale_, Apr 25 2014 *)
%t CoefficientList[Series[(9 - 80 x)/((1 - x) (1 - 10 x)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Apr 26 2014 *)
%t (10^Range[20] + 71)/9 (* _Alonso del Arte_, Apr 18 2015 *)
%Y Cf. A104482, A093400.
%K easy,nonn
%O 1,1
%A _Ivan Panchenko_, Sep 10 2009