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 A140317 #18 Aug 26 2020 03:06:31
%S A140317 1,12,108,1008,10000,100008,1000041,10000000,100000008,1000000000,
%T A140317 10000000109,100000000080,1000000000116,10000000000144,
%U A140317 100000000000125,1000000000000000,10000000000000152,100000000000000008
%N A140317 Smallest n-digit number divisible by n^2.
%H A140317 Harvey P. Dale, <a href="/A140317/b140317.txt">Table of n, a(n) for n = 1..1000</a>
%F A140317 a(n) = n^2*ceiling(10^(n-1)/n^2). - _Michel Marcus_, Aug 25 2020
%e A140317 a(7) = 1000041 because 1000041 has 7 digits, 1000041/49 = 20409 = 3 * 6803 and no integer between 1000000 and 1000041 is divisible by 7^2 = 49.
%e A140317 a(9) = 100000008 because 100000008 has 9 digits, 100000008/81 = 1234568 = 23 * 154321 and no integer between 100000000 and 100000008 is divisible by 9^2 = 81.
%p A140317 A140317 := proc(n) n^2*ceil(10^(n-1)/n^2) ; end: seq(A140317(n),n=1..30) ; # _R. J. Mathar_, May 31 2008
%t A140317 snd[n_]:=Module[{c=n^2-PowerMod[10,n-1,n^2]},If[Divisible[10^(n-1), n^2], 10^(n-1),10^(n-1)+c]]; Array[snd,20] (* _Harvey P. Dale_, Dec 14 2012 *)
%Y A140317 Cf. A000290, A053041.
%K A140317 easy,nonn,base
%O A140317 1,2
%A A140317 _Jonathan Vos Post_, May 26 2008
%E A140317 More terms from _R. J. Mathar_, May 31 2008