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A319697
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Sum of even squarefree divisors of n.
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4
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0, 2, 0, 2, 0, 8, 0, 2, 0, 12, 0, 8, 0, 16, 0, 2, 0, 8, 0, 12, 0, 24, 0, 8, 0, 28, 0, 16, 0, 48, 0, 2, 0, 36, 0, 8, 0, 40, 0, 12, 0, 64, 0, 24, 0, 48, 0, 8, 0, 12, 0, 28, 0, 8, 0, 16, 0, 60, 0, 48, 0, 64, 0, 2, 0, 96, 0, 36, 0, 96, 0, 8, 0, 76, 0, 40, 0, 112, 0, 12, 0, 84, 0, 64, 0, 88, 0, 24, 0, 48, 0, 48, 0, 96
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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Table[Total[Select[Divisors[n], EvenQ[#]&&SquareFreeQ[#]&]], {n, 100}] (* Harvey P. Dale, May 18 2019 *)
f[2, e_] := 2; f[p_, e_] := p + 1; a[n_] := If[OddQ[n], 0, Times @@ f @@@ FactorInteger[n]]; Array[a, 100] (* Amiram Eldar, Jun 30 2022 *)
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PROG
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(PARI) A319697(n) = sumdiv(n, d, (!(d%2))*issquarefree(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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