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A134322
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Positive integers with fewer non-isolated divisors than isolated divisors. A divisor, k, of n is non-isolated if (k-1) or (k+1) also divides n. A divisor, k, of n is isolated if neither (k-1) nor (k+1) divides n.
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2
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1, 3, 5, 7, 9, 11, 13, 15, 16, 17, 19, 21, 23, 25, 27, 28, 29, 31, 32, 33, 35, 36, 37, 39, 41, 43, 44, 45, 47, 48, 49, 50, 51, 52, 53, 54, 55, 57, 59, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 75, 76, 77, 78, 79, 80, 81, 83, 85, 87, 88, 89, 91, 92, 93, 95, 96, 97, 98, 99, 100
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| All odd positive integers are in the sequence, since every divisor of any odd number is isolated.
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EXAMPLE
| The divisors of 50 are 1,2,5,10,25,50. Of these, 1 and 2 are non-isolated divisors and 5,10,25,50 are isolated divisors. There are fewer non-isolated divisors (2 in number) than isolated divisors (4 in number), so 50 is in the sequence.
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CROSSREFS
| Cf. A134320, A134321.
Sequence in context: A091569 A206545 A120890 * A186328 A063460 A187232
Adjacent sequences: A134319 A134320 A134321 * A134323 A134324 A134325
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Oct 20 2007
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jun 24 2008
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