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Search: id:A054979
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| A054979 |
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e-perfect numbers: numbers n such that the sum of the e-divisors (exponential divisors) of n equals 2n. |
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+0
10
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| 36, 180, 252, 396, 468, 612, 684, 828, 1044, 1116, 1260, 1332, 1476, 1548, 1692, 1800, 1908, 1980, 2124, 2196, 2340, 2412, 2556, 2628, 2700, 2772, 2844, 2988, 3060, 3204, 3276, 3420, 3492, 3636, 3708, 3852, 3924, 4068, 4140, 4284, 4572, 4716
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The e-divisors (or exponential divisors) of x=Product p(i)^r(i) are all numbers of the form Product p(i)^s(i) where s(i) divides r(i) for all i.
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REFERENCES
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R. K. Guy, Unsolved Problems In Number Theory, B17.
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LINKS
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Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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EXAMPLE
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The e-divisors of 36 are 2*3, 4*3, 2*9 and 4*9, and the sum of these = 2*36, so 36 is e-perfect.
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CROSSREFS
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Cf. A051377, A054980.
Sequence in context: A064500 A017054 A127657 this_sequence A102949 A017138 A120465
Adjacent sequences: A054976 A054977 A054978 this_sequence A054980 A054981 A054982
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KEYWORD
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nonn
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AUTHOR
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Jud McCranie (j.mccranie(AT)comcast.net), May 29 2000
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