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A336654
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Numbers k such that lambda(k) is squarefree, where lambda is the Carmichael lambda function (A002322).
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3
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1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 14, 18, 21, 22, 23, 24, 28, 31, 33, 36, 42, 43, 44, 46, 47, 49, 56, 59, 62, 63, 66, 67, 69, 71, 72, 77, 79, 83, 84, 86, 88, 92, 93, 94, 98, 99, 103, 107, 118, 121, 124, 126, 129, 131, 132, 134, 138, 139, 141, 142, 147, 154, 158, 161
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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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The number of terms not exceeding x is (k + o(1)) * x/(log(x)^(1-a)), where a = 0.373955... is Artin's constant (A005596), and k = 0.80328... is another constant (Pappalardi et al., 2003).
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EXAMPLE
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6 is a term since lambda(6) = 2 is squarefree.
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MATHEMATICA
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Select[Range[160], SquareFreeQ[CarmichaelLambda[#]] &]
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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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