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Search: id:A085790
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| A085790 |
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Integers sorted by the sum of their divisors. |
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+0
2
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| 1, 2, 3, 5, 4, 7, 6, 11, 9, 13, 8, 10, 17, 19, 14, 15, 23, 12, 29, 16, 25, 21, 31, 22, 37, 18, 27, 20, 26, 41, 43, 33, 35, 47, 34, 53, 28, 39, 49, 24, 38, 59, 61, 32, 67, 30, 46, 51, 55, 71, 73, 45, 57, 79, 44, 65, 83, 40, 58, 89, 36, 50, 42, 62, 69, 77, 52, 97, 101, 63, 103, 85
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OFFSET
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1,2
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COMMENT
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Integers having the same sum of divisors are sorted in ascending order, e.g. sigma(14)=sigma(15)=sigma(23)=24 -> a(15)=14, a(16)=15, a(17)=23
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EXAMPLE
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a(9)=9, a(10)=13, a(11)=8 because sigma(9)=13=9+3+1, sigma(13)=14=13+1,
sigma(8)=15=8+4+2+1 and there are no other numbers with those sigma values.
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CROSSREFS
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Cf. A000203 (sigma(n)), A007609 (values taken by sigma(n), sorted), A002191 (possible values for sigma(n)).
Sequence in context: A064707 A123882 A102454 this_sequence A117120 A127515 A099424
Adjacent sequences: A085787 A085788 A085789 this_sequence A085791 A085792 A085793
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KEYWORD
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easy,nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), Jul 23 2003
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