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Search: id:A054753
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| A054753 |
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Numbers which are the product of a prime and the square of a different prime. |
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+0
16
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| 12, 18, 20, 28, 44, 45, 50, 52, 63, 68, 75, 76, 92, 98, 99, 116, 117, 124, 147, 148, 153, 164, 171, 172, 175, 188, 207, 212, 236, 242, 244, 245, 261, 268, 275, 279, 284, 292, 316, 325, 332, 333, 338, 356, 363, 369, 387, 388, 404, 412, 423, 425, 428, 436, 452
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(1)=12 because 12=3*2*2
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MATHEMATICA
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lst={}; Do[If[Length[FactorInteger[n]]==2&&((FactorInteger[n][[1, 2]]==2&&FactorInteger[n][[2, 2]]==1)||(FactorInteger[n][[2, 2]]==2&&FactorInteger[n][[1, 2]]==1)), (*Print[n]; *)AppendTo[lst, n]], {n, 10^3}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 21 2008]
Contribution from Zak Seidov (zakseidov(AT)yahoo.com), Jul 19 2009: (Start)
S=Select[Range[12, 452], {1, 2}==Sort[Last/@FactorInteger[ # ]]&]
S=Select[Range[12, 452], (Times@@Divisors@#)^(1/3)==#&] (End)
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CROSSREFS
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Cf. numbers with 6 divisors (A030515) which are not 5th powers of primes (A050997)
Sequence in context: A084679 A072588 A072357 this_sequence A098899 A098770 A091191
Adjacent sequences: A054750 A054751 A054752 this_sequence A054754 A054755 A054756
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KEYWORD
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nonn
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Apr 25 2000
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