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A073181
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Sum of divisors of n which are not greater than the squarefree kernel of n.
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4
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1, 3, 4, 3, 6, 12, 8, 3, 4, 18, 12, 16, 14, 24, 24, 3, 18, 12, 20, 22, 32, 36, 24, 16, 6, 42, 4, 28, 30, 72, 32, 3, 48, 54, 48, 16, 38, 60, 56, 30, 42, 96, 44, 40, 33, 72, 48, 16, 8, 18, 72, 46, 54, 12, 72, 36, 80, 90, 60, 108, 62, 96, 41, 3, 84, 144, 68, 58, 96, 144, 72, 16, 74
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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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EXAMPLE
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The squarefree kernel of 56 = 7 * 2^3 is 14 = 7*2 and the divisors <= 14 of 56 are {1, 2, 4, 7, 8, 14}, therefore a(56) = 1 + 2 + 4 + 7 + 8 + 14 = 36.
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MATHEMATICA
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a[n_] := DivisorSum[n, # &, # <= Times @@ FactorInteger[n][[;; , 1]] &]; Array[a, 100] (* Amiram Eldar, Jul 09 2022 *)
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PROG
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(PARI)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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