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A175760
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Numbers n such that d(n + d(n)) = d(n), where d(n) is the sum of the distinct primes dividing n.
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3
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1, 2, 39, 95, 119, 182, 2130, 2183, 2356, 2623, 3059, 3431, 3825, 6680, 9588, 10170, 10679, 11790, 14039, 14111, 15030, 16199, 16762, 16799, 17766, 19669, 22218, 24505, 26352, 26353, 34443, 34765, 34875, 36594, 37843, 39121, 39479, 39697, 42210, 44051, 45346
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OFFSET
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1,2
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COMMENTS
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The sum of the distinct primes dividing n (A008472) sometimes called sopf(n).
d(1) = 0 because 1 has no prime divisors. So 1 is in this sequence because d(1+0) = d(1). - T. D. Noe, Jul 06 2012
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LINKS
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EXAMPLE
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39 is in the sequence because sopf(39) = 16 and sopf(39 + sopf(39)) = sopf(55 ) = 16.
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MATHEMATICA
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d[n_] := Plus @@ Transpose[FactorInteger[n]][[1]]; Join[{1}, Select[Range[2, 50000], d[# + d[#]] == d[#] &]]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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