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A136176
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Number of exponents in the prime factorization of n which divide n.
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2
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0, 1, 1, 1, 1, 2, 1, 0, 0, 2, 1, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 0, 2, 1, 2, 1, 3, 1, 0, 2, 2, 2, 2, 1, 2, 2, 1, 1, 3, 1, 2, 1, 2, 1, 2, 0, 2, 2, 2, 1, 2, 2, 1, 2, 2, 1, 3, 1, 2, 1, 0, 2, 3, 1, 2, 2, 3, 1, 2, 1, 2, 1, 2, 2, 3, 1, 2, 0, 2, 1, 3, 2, 2, 2, 1, 1, 3, 2, 2, 2, 2, 2, 1, 1, 2, 1, 2, 1, 3, 1, 1, 3
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OFFSET
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1,6
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LINKS
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EXAMPLE
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128000 = 2^10 * 5^3. 10 divides 128000, but 3 does not. So a(128000) = 1.
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MATHEMATICA
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Table[Length[Select[Table[FactorInteger[n][[i, 2]], {i, 1, Length[FactorInteger[n]]}], Mod[n, # ] == 0 &]], {n, 1, 90}] (* Stefan Steinerberger, Dec 21 2007 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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