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A370789
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Ore numbers whose nontrivial divisors are not Ore numbers.
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0
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OFFSET
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1,1
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COMMENTS
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It seems this is a supersequence of A000396 (confirmed for all available terms of A000396).
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LINKS
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EXAMPLE
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The nontrivial divisors of 6 are 2 and 3 that do not belong to A001599, so 6 is a term.
No nontrivial divisor of 6200 is a term of A001599, which makes 6200 a term of the present sequence. On the other hand, 6200 is not a perfect number.
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MATHEMATICA
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oreQ[n_] := IntegerQ[n*DivisorSigma[0, n]/DivisorSigma[1, n]];
ntdNotOreQ[n_] := NoneTrue[Most[Rest[Divisors[n]]], oreQ[#] &];
a001599 = Cases[Import["https://oeis.org/A001599/b001599.txt", "Table"],
{_, _}][[All, 2]];
Select[Rest[a001599], ntdNotOreQ[#] &]
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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