This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A124166 #10 Jun 25 2025 00:46:21
%S A124166 0,100,1100,11100,111100,1111100,11111100,111111100,1111111100,
%T A124166 11111111100,111111111100,1111111111100,11111111111100,
%U A124166 111111111111100,1111111111111100,11111111111111100,111111111111111100,1111111111111111100,11111111111111111100,111111111111111111100
%N A124166 a(n) = 100*(10^n - 1)/9.
%H A124166 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10).
%F A124166 From _Elmo R. Oliveira_, Jun 18 2025: (Start)
%F A124166 G.f.: 100*x/((10*x-1)*(x-1)).
%F A124166 E.g.f.: 100*exp(x)*(exp(9*x) - 1)/9.
%F A124166 a(n) = 100*A002275(n) = 10*A105279(n).
%F A124166 a(n) = A161770(n)/10 for n >= 1.
%F A124166 a(n) = 11*a(n-1) - 10*a(n-2). (End)
%p A124166 a:=n->sum (10^(n-j+2),j=0..n): seq(a(n),n=0..28);
%t A124166 Table[FromDigits[PadLeft[{0,0},n,1]],{n,2,20}] (* _Harvey P. Dale_, Jul 24 2012 *)
%o A124166 (PARI) concat(0, Vec(100*x/((1-x)*(1-10*x)) + O(x^20))) \\ _Elmo R. Oliveira_, Jun 18 2025
%Y A124166 Cf. A002275, A105279, A161770.
%K A124166 easy,nonn
%O A124166 0,2
%A A124166 _Zerinvary Lajos_, Dec 02 2006
%E A124166 More terms from _Elmo R. Oliveira_, Jun 18 2025