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Search: id:A145551
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| A145551 |
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Numbers n such that product of divisors of n / sum of divisors of n is an integer. |
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+0
1
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| 1, 6, 28, 30, 66, 84, 102, 120, 210, 270, 318, 330, 364, 420, 462, 496, 510, 546, 570, 642, 672, 690, 714, 840, 868, 870, 924, 930, 966, 1080, 1092, 1122, 1320, 1410, 1428, 1488, 1518, 1590, 1638, 1722, 1770, 1782, 1890, 1932, 2040, 2130, 2226, 2280, 2310
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A007955(n)/A000203(n) is an integer
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REFERENCES
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Zhang Wengpeng : On the divisor products and proper divisor products sequences,Smarandache Notions Journal,Volume 13, Issue 1-2-3(Spring 2002),pp. 128 - 133, ISSN:1084-2810
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MAPLE
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A007955 := proc(n) local dvs, d ; dvs := numtheory[divisors](n) ; mul(d, d=dvs) ; end: A000203 := proc(n) local dvs, d ; dvs := numtheory[divisors](n) ; add(d, d=dvs) ; end: isA145551 := proc(n) RETURN(A007955(n) mod A000203(n) = 0) ; end: for n from 1 to 10000 do if isA145551(n) then printf("%d, ", n) ; fi; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 14 2008]
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CROSSREFS
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Cf. A000203, A007955, A140480
Sequence in context: A101454 A091911 A105402 this_sequence A083865 A117948 A071834
Adjacent sequences: A145548 A145549 A145550 this_sequence A145552 A145553 A145554
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KEYWORD
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easy,nonn
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AUTHOR
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Ctibor O. Zizka (c.zizka(AT)seznam.cz), Oct 13 2008
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EXTENSIONS
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90, 96, 108, 126, 132, 140 removed, extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 14 2008
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