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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 (list; graph; refs; listen; history; text; internal format)
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, 493-504; 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

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Last modified January 26 20:11 EST 2020. Contains 331288 sequences. (Running on oeis4.)