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 A276352 #35 Aug 14 2024 20:45:29
%S A276352 0,90,9900,999000,99990000,9999900000,999999000000,99999990000000,
%T A276352 9999999900000000,999999999000000000,99999999990000000000,
%U A276352 9999999999900000000000,999999999999000000000000,99999999999990000000000000,9999999999999900000000000000,999999999999999000000000000000
%N A276352 a(n) = 100^n - 10^n.
%H A276352 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (110,-1000).
%F A276352 a(n) = floor((1000^n)/(10^n + 1)).
%F A276352 a(n) = A002283(n)*A011557(n).
%F A276352 a(n) = 9*A138147(n), for n>0.
%F A276352 a(n) = A168624(n) - 1.
%F A276352 a(n) = Sum_{k=1..n} 9*10^(2n-k).
%F A276352 a(n) = ((10^n)*A002283(2n))/(10^n + 1).
%F A276352 From _Chai Wah Wu_, Sep 01 2016: (Start)
%F A276352 a(n) = 110*a(n-1) - 1000*a(n-2) for n > 1.
%F A276352 G.f.: 90*x/((10*x - 1)*(100*x - 1)). (End)
%F A276352 E.g.f.: exp(10*x)*(exp(90*x) - 1). - _Elmo R. Oliveira_, Aug 14 2024
%p A276352 A276352:=n->100^n-10^n: seq(A276352(n), n=0..20); # _Wesley Ivan Hurt_, Sep 07 2016
%t A276352 Table[100^n - 10^n, {n, 0, 10}] (* _Alonso del Arte_, Aug 31 2016 *)
%o A276352 (PARI) a(n)=100^n-10^n \\ _Charles R Greathouse IV_, Sep 01 2016
%o A276352 (Magma) [100^n-10^n : n in [0..20]]; // _Wesley Ivan Hurt_, Sep 07 2016
%Y A276352 Cf. A002283, A011557, A138147, A168624.
%K A276352 nonn,easy
%O A276352 0,2
%A A276352 _Carauleanu Marc_, Aug 31 2016