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A368714
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Numbers whose maximal exponent in their prime factorization is even.
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9
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1, 4, 9, 12, 16, 18, 20, 25, 28, 36, 44, 45, 48, 49, 50, 52, 60, 63, 64, 68, 75, 76, 80, 81, 84, 90, 92, 98, 99, 100, 112, 116, 117, 121, 124, 126, 132, 140, 144, 147, 148, 150, 153, 156, 162, 164, 169, 171, 172, 175, 176, 180, 188, 192, 196, 198, 204, 207, 208
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OFFSET
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1,2
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COMMENTS
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First differs from A240112 at n = 30.
Numbers k such that A051903(k) is even.
The asymptotic density of this sequence is Sum_{k>=2} (-1)^k * (1 - 1/zeta(k)) = 0.27591672059822700769... .
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LINKS
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MATHEMATICA
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Select[Range[210], # == 1 || EvenQ[Max[FactorInteger[#][[;; , 2]]]] &]
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PROG
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(PARI) lista(kmax) = for(k = 1, kmax, if(k == 1 || !(vecmax(factor(k)[, 2])%2), print1(k, ", ")));
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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