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A138789
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a(n) = number of distinct prime divisors of A104759(n).
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17
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0, 2, 2, 2, 3, 2, 2, 3, 3, 2, 2, 4, 4, 2, 5, 4, 2, 3, 7, 4, 4, 3, 3, 2, 5, 3, 5, 2, 3, 6, 6, 3, 3, 5, 5, 7, 3, 3, 4, 3, 3, 4, 4, 5, 3, 5, 7, 3, 5, 6, 6, 5, 4, 5, 2, 6, 4, 6, 4, 4, 7, 6, 5, 5, 6, 9
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OFFSET
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1,2
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COMMENTS
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Indices where number 1 occured in this sequence see A138790
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LINKS
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MATHEMATICA
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lst = {}; Do[lst = Join[lst, IntegerDigits[n]], {n, 1, 50}]; Table[Length[FactorInteger[FromDigits[Reverse[lst[[Range[1, n]]]]]]], {n, 1, Length[lst]}] (* Robert Price, Mar 24 2015 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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