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Search: id:A058972
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| A058972 |
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For a rational number p/q let f(p/q) = sum of aliquot divisors of p+q divided by number of divisors of p+q; sequence gives numbers n such that, starting at n/1 and iterating f, an integer is eventually reached. |
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+0
7
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| 3, 9, 15, 24, 25, 29, 33, 35, 50, 51, 55, 57, 59, 63, 73, 79, 80, 81, 85, 87, 89, 90, 95, 99, 105, 119, 120, 121, 128, 131, 139, 143, 145, 169, 177, 179, 181, 183, 193, 195, 201, 203, 204, 211, 215, 217, 218, 219, 221, 225, 227, 233, 247, 248, 255, 273, 275, 288
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Matthew M. Conroy, Home page (listed instead of email address)
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EXAMPLE
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f(9/1) = 8/4 = 2, an integer, so 9 is in the sequence; f(10/1) = 1/2, and f(1/2)=1/2, so 10 is not in the sequence.
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CROSSREFS
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Cf. A058971, A058973.
Sequence in context: A064539 A029482 A139419 this_sequence A026222 A099989 A085046
Adjacent sequences: A058969 A058970 A058971 this_sequence A058973 A058974 A058975
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas, Jan 14 2001
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EXTENSIONS
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Corrected and extended by Matthew M. Conroy, Apr 18 2001
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