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%I #13 Jan 24 2020 10:53:34
%S 1,1,2,3,1,3,3,2,2,2,3,3,4,4,3,4,3,3,4,5,4,4,4,4,4,5,3,4,2,4,4,5,4,4,
%T 4,8,2,2,2,3,5,4,6,6,1,5,3,4,5,4,5,8,4,2,5,5,5,2,4,4,6,4,2,4,3,4,6,3,
%U 6,9,4,7,5,3,5,7,3,6,5,6,4,7,4,5,3,5,4
%N Number of distinct prime divisors of 33...337 (with n 3s).
%C Number of distinct prime factors of (10^(n + 1) - 1)/3 + 4. - _Stefan Steinerberger_, Mar 06 2006
%H Amiram Eldar, <a href="/A104483/b104483.txt">Table of n, a(n) for n = 0..199</a>
%F a(n) = A001221(A173766(n+1)). - _Amiram Eldar_, Jan 24 2020
%e The number of distinct prime divisors of 37 is 1 (prime).
%e The number of distinct prime divisors of 337 is 1 (prime).
%e The number of distinct prime divisors of 3337 is 2.
%t Table[Length[FactorInteger[(10^(n + 1) - 1)/3 + 4]], {n, 1, 50}] (* _Stefan Steinerberger_, Mar 06 2006 *)
%Y Cf. A001221, A173766.
%K nonn,base
%O 0,3
%A _Parthasarathy Nambi_, Apr 18 2005
%E More terms from _Stefan Steinerberger_, Mar 06 2006
%E More terms from _Amiram Eldar_, Jan 24 2020