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A291791
Numbers n whose trajectory under the iteration of k -> (sigma(k)+phi(k))/2 reaches a fraction.
5
4, 8, 9, 12, 14, 15, 16, 18, 20, 24, 25, 28, 32, 33, 34, 35, 36, 42, 48, 49, 50, 54, 55, 56, 62, 63, 64, 69, 70, 72, 76, 77, 78, 81, 84, 85, 86, 87, 88, 90, 93, 94, 95, 96, 98, 99, 100, 102, 104, 105, 108, 110, 111
OFFSET
1,1
COMMENTS
It would be nice to have an independent characterization of these numbers (not involving the map in the definition).
LINKS
CROSSREFS
Union of A028982 \ {1,2} and A290001. Also the complement of A289997.
Sequence in context: A294574 A010453 A078136 * A037973 A044844 A145190
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 03 2017
EXTENSIONS
B-file shortened by N. J. A. Sloane, Sep 17 2017
STATUS
approved