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 A004219 #13 Jan 03 2022 21:26:47
%S A004219 0,3,4,6,6,7,8,9,9,10,10,10,11,11,11,12,12,12,12,13,13,13,13,13,13,14,
%T A004219 14,14,14,14,14,15,15,15,15,15,15,15,15,16,16,16,16,16,16,16,16,16,16,
%U A004219 16,17,17,17,17,17,17,17,17,17,17,17,17,17,18,18,18,18,18
%N A004219 a(n) = floor(10*log_10(n)).
%H A004219 Vincenzo Librandi, <a href="/A004219/b004219.txt">Table of n, a(n) for n = 1..10000</a>
%F A004219 a(n) = floor(10*log_10(n)) = floor(10(log(n)/log(10))) =
%F A004219 floor(10(log(n)/(log(2) + log(5)))). - _Alonso del Arte_, Dec 24 2013
%e A004219 a(2) = 3 because 10(log(2)/log(10)) = 3.0102999566398...
%e A004219 a(3) = 4 because 10(log(3)/log(10)) = 4.7712125471966...
%e A004219 a(4) = 6 because 10(log(4)/log(10)) = 6.0205999132796...
%t A004219 Table[Floor[10Log[10, n]], {n, 75}] (* _Alonso del Arte_, Dec 24 2013 *)
%Y A004219 Cf. A004234.
%K A004219 nonn
%O A004219 1,2
%A A004219 _N. J. A. Sloane_
%E A004219 More terms from _Alonso del Arte_, Dec 24 2013