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A125640
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Primitive doubly abundant numbers - doubly abundant numbers that are not the multiple of another doubly abundant number.
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1
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24, 30, 42, 54, 66, 78, 102, 114, 138, 140, 174, 176, 186, 222, 224, 246, 258, 282, 308, 318, 340, 354, 364, 366, 380, 402, 426, 438, 440, 474, 476, 498, 520, 532, 534, 580, 582, 606, 618, 642, 644, 654, 678, 704, 762, 786, 812, 822, 834, 852, 868, 894, 896
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Are there infinitely many primitive doubly abundant numbers?
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EXAMPLE
| 42 is a primitive doubly abundant number because it is abundant (s(42) = 54), the sum of its proper divisors is abundant (s(54) = 66) and no divisor of 42 is doubly abundant.
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CROSSREFS
| Cf. A005101, A125639.
Sequence in context: A030626 A125639 A076496 * A141545 A106682 A175258
Adjacent sequences: A125637 A125638 A125639 * A125641 A125642 A125643
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KEYWORD
| nonn
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AUTHOR
| Gabriel Cunningham (gabriel.cunningham(AT)gmail.com), Nov 28 2006
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