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Search: id:A162142
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| A162142 |
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Numbers that are the cube of a product of two distinct primes. |
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+0
4
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| 216, 1000, 2744, 3375, 9261, 10648, 17576, 35937, 39304, 42875, 54872, 59319, 97336, 132651, 166375, 185193, 195112, 238328, 274625, 328509, 405224, 456533, 551368, 614125, 636056, 658503, 753571, 804357, 830584, 857375, 1191016
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Subset of A046306, of A000578, and of A007774. [R. J. Mathar, Jun 27 2009]
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FORMULA
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a(n) = (A006881(n))^3 = A000578(A006881(n)). [R. J. Mathar, Jun 27 2009]
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EXAMPLE
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216=2^3*3^3. 1000=2^3*5^3. 2744=2^3*7^3.
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MATHEMATICA
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fQ[n_]:=Last/@FactorInteger[n]=={3, 3}; lst={}; Do[If[fQ[n], AppendTo[lst, n]], {n, 6*9!}]; lst
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CROSSREFS
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Sequence in context: A135590 A111029 A124581 this_sequence A016863 A033698 A121683
Adjacent sequences: A162139 A162140 A162141 this_sequence A162143 A162144 A162145
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KEYWORD
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nonn
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AUTHOR
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Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 25 2009
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EXTENSIONS
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Definition rephrased by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 27 2009
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