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A141346
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Sum of the distinct digits of the prime factors of n.
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1
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0, 2, 3, 2, 5, 5, 7, 2, 3, 7, 1, 5, 4, 9, 8, 2, 8, 5, 10, 7, 10, 3, 5, 5, 5, 6, 3, 9, 11, 10, 4, 2, 4, 10, 12, 5, 10, 12, 4, 7, 5, 12, 7, 3, 8, 5, 11, 5, 7, 7, 11, 6, 8, 5, 6, 9, 13, 11, 14, 10, 7, 6, 10, 2, 9, 6, 13, 10, 5, 14, 8, 5, 10, 12, 8, 12, 8, 6, 16, 7, 3, 7, 11, 12, 13, 9, 14, 3, 17, 10
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Motivated by seeking an explanation for A080592. For n >= 2, 1 <= a(n) <= 45. For n >= 1, a(n) <= A095402(n).
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EXAMPLE
| a(44) = 3 as 44 = 2^2 * 11 and the sum of the distinct digits of the prime factors is 1 + 2 (whereas A095402(44) = 4 = 1 + 1 + 2).
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MATHEMATICA
| Join[{0}, Rest[Total[Union[Flatten[IntegerDigits/@Transpose[ FactorInteger[ #]][[1]]]]]&/@Range[90]]] (* From Harvey P. Dale, Nov 30 2011 *)
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CROSSREFS
| Cf. A095402, A080592, A008472.
Sequence in context: A144310 A035361 A137851 * A095402 A086294 A075860
Adjacent sequences: A141343 A141344 A141345 * A141347 A141348 A141349
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KEYWORD
| base,nonn
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AUTHOR
| Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jun 26 2008
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