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Search: id:A059992
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| A059992 |
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Numbers with an increasing number of nonprime divisors. |
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+0
1
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| 1, 4, 8, 12, 24, 36, 48, 60, 72, 120, 180, 240, 360, 720, 840, 1080, 1260, 1440, 1680, 2160, 2520, 4320, 5040, 7560, 10080, 15120, 20160, 25200, 27720, 30240, 45360, 50400, 55440, 75600, 83160, 110880, 151200, 166320, 221760, 277200, 332640
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(4)=12 because twelve has 4 nonprime divisors {1, 4, 6 and 12} whereas a(3)=8 has only 3; and twelve is the first number greater than eight which exhibits this property.
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MATHEMATICA
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l = 0; Do[ c = Count[PrimeQ[ Divisors[n] ], False]; If[c > l, l = c; Print[n] ], {n, 1, 10^6} ]
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CROSSREFS
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Cf. A055079, A002182.
Sequence in context: A015781 A130643 A014617 this_sequence A050570 A102110 A055079
Adjacent sequences: A059989 A059990 A059991 this_sequence A059993 A059994 A059995
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 08 2001
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