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Search: id:A143610
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| A143610 |
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Numbers of the form p^2*q^3, where p,q are distinct primes. |
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+0
3
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| 72, 108, 200, 392, 500, 675, 968, 1125, 1323, 1352, 1372, 2312, 2888, 3087, 3267, 4232, 4563, 5324, 6125, 6728, 7688, 7803, 8575, 8788, 9747, 10952, 11979, 13448, 14283, 14792, 15125, 17672, 19652, 19773, 21125, 22472, 22707, 25947, 27436
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Also: numbers with prime signature {3,2}.
This is a subsequence of A114128.
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LINKS
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Project Euler, Problem 200.
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EXAMPLE
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The first elements of this sequence are 3^2*2^3=72, 2^2*3^3=108, 5^2*2^3=200.
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MATHEMATICA
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f[n_]:=Last/@FactorInteger[n]=={2, 3}||Last/@FactorInteger[n]=={3, 2}; lst={}; Do[If[f[n], AppendTo[lst, n]], {n, 9!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 09 2009]
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PROGRAM
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(PARI) for(n=1, 10^5, omega(n)==2|next; vecsort(factor(n)[, 2])==[2, 3]~ & print1(n", "))
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CROSSREFS
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Cf. A114128.
Sequence in context: A072412 A052486 A114128 this_sequence A166987 A078667 A090784
Adjacent sequences: A143607 A143608 A143609 this_sequence A143611 A143612 A143613
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KEYWORD
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easy,nonn
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AUTHOR
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M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Aug 27 2008
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