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A090342
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Difference between the sums of the prime factors, including multiplicity, of n and those of n + 3.
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4
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-4, -3, -2, -3, -1, -1, 0, -5, -1, -6, 2, -1, 5, -8, 0, -11, 8, -2, 6, -14, 1, 3, 8, 0, -1, -14, -1, -20, 19, -4, 12, -2, 4, -18, -9, -6, 26, -20, 4, -32, 26, 1, 18, -32, 0, 11, 35, -9, -3, -41, 9, 1, 40, -11, -15, -46, 10, -30, 26, -1, 49, 15, -3, -55, -3, -10, 53, -50, 14, -59, 32, -1, 50, 21, -5, -56, 5, 6, 36, -70, -2, 21, 38
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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a(24)=0 because 24=2*2*2*3, 27=3*3*3 and (2+2+2+3)-(3+3+3)=0.
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MATHEMATICA
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Join[{-4}, #[[1]]-#[[4]]&/@(Partition[Table[Total[Flatten[Table[#[[1]], #[[2]]]&/@ FactorInteger[n]]], {n, 2, 90}], 4, 1])] (* Harvey P. Dale, Sep 16 2018 *)
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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Charles K. Layman (cklayman(AT)juno.com), Nov 25 2003
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STATUS
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approved
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