A325654 revision #16
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A325654
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Numbers m with a divisor d satisfying sigma(d) = 2*m.
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2
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6, 28, 496, 8128, 60480, 65520, 4357080, 33550336, 47139840, 91065600, 285981696, 2758909440, 8589869056, 87722956800, 132867440640, 137438691328, 306007080960, 806062473216, 1409150457792, 363485766938112, 12177456042320640, 29884246553283840
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OFFSET
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1,1
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COMMENTS
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Even perfect numbers from A000396 are terms.
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LINKS
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EXAMPLE
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60480 is a term because 30240 divides 60480 and sigma(30240) = 120960 = 2*60480.
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PROG
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(MAGMA) [n: n in [1..100000] | #[d: d in Divisors(n) | SumOfDivisors(d) eq 2*n] gt 0]
(PARI) isok(n) = fordiv(n, d, if (sigma(d) == 2*n, return(1))); 0; \\ Michel Marcus, May 12 2019
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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