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 A037182 #16 Jun 29 2023 16:03:56
%S A037182 0,45,4950,499500,49995000,4999950000,499999500000,49999995000000,
%T A037182 4999999950000000,499999999500000000,49999999995000000000,
%U A037182 4999999999950000000000,499999999999500000000000,49999999999995000000000000,4999999999999950000000000000
%N A037182 a(n) = 10^n*(10^n-1) / 2.
%C A037182 Sum of all numbers with <= n digits.
%H A037182 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (110, -1000).
%F A037182 Sum_{i=1..10^n-1} i = the (10^n-1)th triangular number (A000217). - _Marvin Ray Burns_
%F A037182 From _Chai Wah Wu_, Mar 17 2018: (Start)
%F A037182 a(n) = 110*a(n-1) - 1000*a(n-2) for n > 1.
%F A037182 G.f.: 45*x/((10*x - 1)*(100*x - 1)). (End)
%t A037182 a[n_] := 10^n(10^n - 1)/2; Table[ a[n], {n, 0, 12}] (* _Robert G. Wilson v_, Dec 24 2004 *)
%Y A037182 Partial sums of A101291.
%K A037182 nonn,easy
%O A037182 0,2
%A A037182 _Marvin Ray Burns_