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Search: id:A125493
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| A125493 |
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Composite deficient numbers. |
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+0
1
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| 4, 8, 9, 10, 14, 15, 16, 21, 22, 25, 26, 27, 32, 33, 34, 35, 38, 39, 44, 45, 46, 49, 50, 51, 52, 55, 57, 58, 62, 63, 64, 65, 68, 69, 74, 75, 76, 77, 81, 82, 85, 86, 87, 91, 92, 93, 94, 95, 98, 99, 105, 106, 110, 111, 115, 116, 117, 118, 119, 121, 122, 123, 124, 125, 128
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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22 is in the sequence because it is composite and its sum of divisors 1+2+11+22=36 is less than 2*22.
The integer 15 is in the sequence because it is composite and the sum of its proper divisors is 1+3+5<15. The integer 18 is not in the sequence because, although composite, the sum of its proper divisors is 1+2+3+6+9>18.
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MAPLE
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with(numtheory): a:=proc(n) if sigma(n)<2*n and bigomega(n)>1 then n else fi end: seq(a(n), n=1..160); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 01 2007
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CROSSREFS
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Cf. A005100 = deficient numbers.
Sequence in context: A096529 A144754 A080970 this_sequence A141608 A094906 A078542
Adjacent sequences: A125490 A125491 A125492 this_sequence A125494 A125495 A125496
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KEYWORD
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nonn
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AUTHOR
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Tanya Khovanova (tanyakh(AT)yahoo.com), Dec 27 2006
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 01 2007
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