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 A104889 #11 Jan 27 2020 08:26:39
%S A104889 1,2,1,2,3,2,2,4,1,3,2,3,2,2,2,2,3,3,1,5,4,4,4,7,1,4,2,5,3,3,3,3,3,6,
%T A104889 4,5,3,2,3,5,6,7,4,4,4,2,5,3,3,6,4,6,2,5,3,5,3,6,4,6,4,6,3,5,6,6,4,5,
%U A104889 2,4,7,7,3,5,3,3,3,5,4,10,5,4,3,5,3,2,4
%N A104889 Number of distinct prime divisors of 44...447 (with n 4s).
%C A104889 Also number of distinct prime factors of (10^(n + 1) - 1)*4/9 + 3. - _Stefan Steinerberger_, Feb 21 2006
%H A104889 Amiram Eldar, <a href="/A104889/b104889.txt">Table of n, a(n) for n = 1..201</a>
%F A104889 a(n) = A001221(A173772(n+1)). - _Amiram Eldar_, Jan 27 2020
%e A104889 Number of distinct prime divisors of 47 is 1 (prime).
%e A104889 Number of distinct prime divisors of 447 is 2.
%e A104889 Number of distinct prime divisors of 4447 is 1 (prime).
%t A104889 Table[Length[FactorInteger[(10^(n + 1) - 1)*4/9 + 3]], {n, 1, 40}] (* _Stefan Steinerberger_, Feb 21 2006 *)
%Y A104889 Cf. A001221, A104564, A173772.
%K A104889 nonn
%O A104889 1,2
%A A104889 _Parthasarathy Nambi_, Apr 24 2005
%E A104889 More terms from _Stefan Steinerberger_, Feb 21 2006
%E A104889 Offset corrected and more terms added by _Amiram Eldar_, Jan 27 2020