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A104889 Number of distinct prime divisors of 44...447 (with n 4s). 2

%I

%S 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 4,5,3,2,3,5

%N Number of distinct prime divisors of 44...447 (with n 4s).

%C Also number of distinct prime factors of (10^(n + 1) - 1)*4/9 + 3. - _Stefan Steinerberger_, Feb 21 2006

%e Number of distinct prime divisors of 47 is 1 (prime).

%e Number of distinct prime divisors of 447 is 2.

%e Number of distinct prime divisors of 4447 is 1 (prime).

%t Table[Length[FactorInteger[(10^(n + 1) - 1)*4/9 + 3]], {n, 1, 40}] (* _Stefan Steinerberger_, Feb 21 2006 *)

%Y Cf. A104564.

%K nonn

%O 0,2

%A _Parthasarathy Nambi_, Apr 24 2005

%E More terms from _Stefan Steinerberger_, Feb 21 2006

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Last modified May 26 04:46 EDT 2019. Contains 323579 sequences. (Running on oeis4.)