

A234286


Positive odd numbers n such that 2m  sigma(m) is never equal to n, where sigma(.) is the sum of divisors function A000203. Conjectural.


4



3, 9, 13, 15, 17, 21, 23, 27, 29, 31, 33, 35, 39, 43, 45, 49
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OFFSET

1,1


COMMENTS

The terms shown here are conjectural, based on a search up to 10^20 made by Davis et al. (2013).


LINKS

Table of n, a(n) for n=1..16.
Nichole Davis, Dominic Klyve and Nicole Kraght, On the difference between an integer and the sum of its proper divisors, Involve, Vol. 6 (2013), No. 4, 493504; DOI: 10.2140/involve.2013.6.493


CROSSREFS

Cf. A000203, A033879 (2n  sigma(n)).
For negative values of n see A234285.
Sequence in context: A070353 A029458 A050571 * A193927 A111230 A046865
Adjacent sequences: A234283 A234284 A234285 * A234287 A234288 A234289


KEYWORD

nonn,more,hard


AUTHOR

N. J. A. Sloane, Dec 28 2013


STATUS

approved



