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Search: id:A071143
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| A071143 |
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Numbers n such that sum of distinct primes dividing n is divisible by the largest prime dividing n. Also n has exactly 4 distinct prime factors and n is square-free. |
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| 3135, 6279, 8855, 10695, 11571, 16095, 17255, 17391, 20615, 20735, 26691, 28083, 31031, 36519, 41151, 41615, 45695, 46655, 47859, 48495, 50439, 54131, 56823, 57239, 59295, 61295, 66215, 72611, 76055, 76479, 80135, 84135, 88595, 89999
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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A008472(n)/A006530(n) is integer; A001221(n)=4, n is square-free.
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EXAMPLE
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n=pqrs, p<q<r<s, p+q+r+s=ks; n=6279=3.7.13,23, sum=3+7+13+23=2.23
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MATHEMATICA
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ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] sb[x_] := Apply[Plus, ba[x]] ma[x_] := Part[Reverse[Flatten[FactorInteger[x]]], 2] amo[x_] := Abs[MoebiusMu[x]] Do[s=sb[n]/ma[n]; If[IntegerQ[s]&&Equal[lf[n], 4]&& !Equal[amo[n], 0], Print[{n, ba[n]}]], {n, 2, 1000000}]
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CROSSREFS
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Cf. A008472, A006530, A000961, A025475, A037074, A071139-A071147.
Sequence in context: A045172 A131276 A045075 this_sequence A061048 A086103 A031644
Adjacent sequences: A071140 A071141 A071142 this_sequence A071144 A071145 A071146
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), May 13 2002
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