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A351047
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a(n) = Sum_{k=1..n} n^rad(k).
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0
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1, 6, 39, 100, 3305, 54726, 958447, 2392776, 5375169, 10011102310, 311270518031, 804967791420, 304805198256481, 11910060539653290, 469042238075266815, 1229501390272865296, 830281003630789139585, 2193053904527215207698, 1983916064827419873906079
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(4) = 100; a(4) = Sum_{k=1..4} 4^rad(k) = 4^rad(1) + 4^rad(2) + 4^rad(3) + 4^rad(4) = 4^1 + 4^2 + 4^3 + 4^2 = 100.
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MATHEMATICA
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a[n_] := Sum[n^Times @@ FactorInteger[k][[;; , 1]], {k, 1, n}]; Array[a, 20] (* Amiram Eldar, Feb 01 2022 *)
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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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