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 A104889 Number of distinct prime divisors of 44...447 (with n 4s). 2
 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, 4, 5, 3, 2, 3, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Also number of distinct prime factors of (10^(n + 1) - 1)*4/9 + 3. - Stefan Steinerberger, Feb 21 2006 LINKS EXAMPLE Number of distinct prime divisors of 47 is 1 (prime). Number of distinct prime divisors of 447 is 2. Number of distinct prime divisors of 4447 is 1 (prime). MATHEMATICA Table[Length[FactorInteger[(10^(n + 1) - 1)*4/9 + 3]], {n, 1, 40}] (* Stefan Steinerberger, Feb 21 2006 *) CROSSREFS Cf. A104564. Sequence in context: A283845 A058071 A174961 * A290979 A117910 A275435 Adjacent sequences:  A104886 A104887 A104888 * A104890 A104891 A104892 KEYWORD nonn AUTHOR Parthasarathy Nambi, Apr 24 2005 EXTENSIONS More terms from Stefan Steinerberger, Feb 21 2006 STATUS approved

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Last modified April 18 08:37 EDT 2019. Contains 322209 sequences. (Running on oeis4.)