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Search: id:A072499
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| A072499 |
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Product of divisors of n which are <= n^(1/2). |
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+0
4
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| 1, 1, 1, 2, 1, 2, 1, 2, 3, 2, 1, 6, 1, 2, 3, 8, 1, 6, 1, 8, 3, 2, 1, 24, 5, 2, 3, 8, 1, 30, 1, 8, 3, 2, 5, 144, 1, 2, 3, 40, 1, 36, 1, 8, 15, 2, 1, 144, 7, 10, 3, 8, 1, 36, 5, 56, 3, 2, 1, 720, 1, 2, 21, 64, 5, 36, 1, 8, 3, 70, 1, 1152, 1, 2, 15, 8, 7, 36, 1, 320, 27, 2, 1, 1008, 5, 2, 3, 64, 1
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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a(1) = 1 and a(24) = 24. For each pair of primes p,q such that p < q < p^2, if n = p^3*q, then a(n) = n. There are others as well; e.g. a(40)=40. - Don Reble, Aug 02, 2002.
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EXAMPLE
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a(20) = 8. The divisors of 20 are 1,2,4,5,10 and 20. a(20) = 1*2 *4= 8.
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CROSSREFS
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Cf. A072500, A072501.
Sequence in context: A034880 A070966 A072504 this_sequence A060272 A129985 A085243
Adjacent sequences: A072496 A072497 A072498 this_sequence A072500 A072501 A072502
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jul 20 2002
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EXTENSIONS
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More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Feb 02 2003
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