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A134322
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.
2
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
OFFSET
1,2
COMMENTS
All odd positive integers are in the sequence, since every divisor of any odd number is isolated.
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.
CROSSREFS
Sequence in context: A293703 A120890 A321499 * A186328 A063460 A329831
KEYWORD
nonn
AUTHOR
Leroy Quet, Oct 20 2007
EXTENSIONS
Extended by Ray Chandler, Jun 24 2008
STATUS
approved