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 A017936 #18 Sep 08 2022 08:44:43
%S A017936 1,4,10,32,100,317,1000,3163,10000,31623,100000,316228,1000000,
%T A017936 3162278,10000000,31622777,100000000,316227767,1000000000,3162277661,
%U A017936 10000000000,31622776602,100000000000,316227766017,1000000000000
%N A017936 Smallest number whose square has n digits.
%H A017936 Vincenzo Librandi, <a href="/A017936/b017936.txt">Table of n, a(n) for n = 1..1000</a>
%F A017936 a(n) = ceiling(10^((n-1)/2)).
%e A017936 a(4) = 32, 32^2 = 1024 has 4 digits, while 31^2 = 961 has 3 digits.
%p A017936 A061436 := n->ceil(10^((n-1)/2));
%t A017936 Table[Ceiling[Sqrt[10^n]],{n,0,30}] (* _Harvey P. Dale_, Jan 19 2012 *)
%o A017936 (Magma) [Ceiling(10^((n-1)/2)): n in [1..30]]; // _Vincenzo Librandi_, Oct 21 2011
%Y A017936 Cf. A061432.
%K A017936 nonn,base,easy
%O A017936 1,2
%A A017936 _N. J. A. Sloane_
%E A017936 More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001
%E A017936 More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003