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A341676
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The unique superior prime divisor of each number that has one.
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26
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2, 3, 2, 5, 3, 7, 3, 5, 11, 13, 7, 5, 17, 19, 5, 7, 11, 23, 5, 13, 7, 29, 31, 11, 17, 7, 37, 19, 13, 41, 7, 43, 11, 23, 47, 7, 17, 13, 53, 11, 19, 29, 59, 61, 31, 13, 11, 67, 17, 23, 71, 73, 37, 19, 11, 13, 79, 41, 83, 17, 43, 29, 11, 89, 13, 23, 31, 47, 19
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OFFSET
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1,1
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COMMENTS
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We define a divisor d|n to be superior if d >= n/d. Superior divisors are counted by A038548 and listed by A161908. Numbers with a superior prime divisor are listed by A063538.
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LINKS
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EXAMPLE
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The sequence of superior prime divisors begins: {}, {2}, {3}, {2}, {5}, {3}, {7}, {}, {3}, {5}, {11}, {}, {13}, {7}, {5}, {}, {17}, {}, {19}, {5}, ...
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MATHEMATICA
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Join@@Table[Select[Divisors[n], PrimeQ[#]&&#>=n/#&], {n, 100}]
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CROSSREFS
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These divisors (superior prime) are counted by A341591.
The strictly superior version is A341643.
A033676 selects the greatest inferior divisor.
A033677 selects the smallest superior divisor.
A038548 counts superior (or inferior) divisors.
A056924 counts strictly superior (or strictly inferior) divisors.
A060775 selects the greatest strictly inferior divisor.
A140271 selects the smallest strictly superior divisor.
- Strictly Superior: A048098, A064052, A238535, A341594, A341595, A341642, A341643, A341644, A341645, A341646, A341673.
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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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