%I #87 Jan 16 2024 17:21:42
%S 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
%T 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
%U 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9
%N Constant sequence: the all 9's sequence.
%C Continued fraction expansion of (9 + sqrt(85))/2. - _Bruno Berselli_, Mar 15 2011
%C Also decimal expansion of 0.9999... = 1. - _Jianing Song_, Jul 12 2018
%C Contains "SUB[48]: 200 Terabytes of nines", proposed in Randall Munroe's xkcd Web Comic #2016 as a subsequence. - _Hugo Pfoertner_, Jul 15 2018
%C Also digits of the 10-adic integer -1. - _Stefano Spezia_, Jan 21 2021
%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=1017">Encyclopedia of Combinatorial Structures 1017</a>
%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H Randall Munroe, <a href="https://xkcd.com/2016/">OEIS Submissions</a>, xkcd Web Comic #2016, Jul 06 2018.
%H Anderson Norton and Michael Baldwin, <a href="http://math.coe.uga.edu/TME/Issues/v21n2/v21n2_Norton&Baldwin_Abs.html">Does 0.999... really equal 1?</a>, The Math Educ. 21 (2) (2012) 58-67.
%H <a href="/index/Di#divseq">Index to divisibility sequences</a>
%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1).
%F G.f.: 9/(1-x). - _Bruno Berselli_, Mar 15 2011
%F Equals A158289(n) + A199264(n). - _Arkadiusz Wesolowski_, Nov 30 2011
%F E.g.f.: 9*e^x. - _Vincenzo Librandi_, Jan 26 2012
%t Table[9, {81}] (* _Arkadiusz Wesolowski_, Nov 30 2011 *)
%t IntegerDigits[10^100 - 1] (* _Alonso del Arte_, Jul 09 2018 *)
%t PadRight[{},120,9] (* _Harvey P. Dale_, Jan 28 2020 *)
%o (PARI) a(n)=9 \\ _Charles R Greathouse IV_, Oct 07 2015
%o (Scala) List.fill(100)(9) // _Alonso del Arte_, Jul 08 2018
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_