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A141406
Numbers n where the sum of all of its divisors < sqrt(n) exceeds the sum of all the divisors of m < sqrt(m) for all m<n.
2
1, 2, 6, 12, 20, 24, 30, 40, 48, 60, 72, 90, 120, 168, 180, 240, 336, 360, 420, 480, 504, 600, 630, 672, 720, 840, 1080, 1260, 1440, 1680, 2160, 2520, 3360, 3780, 3960, 4200, 4320, 4620, 5040, 6720, 7560, 9240, 10080, 12600, 13860, 15120, 18480, 20160
OFFSET
1,2
COMMENTS
Conjecture: 3600 is the largest number that belongs to exactly one of this sequence and A141037. - J. Lowell, Aug 05 2020
LINKS
MATHEMATICA
lst = {}; s = -1; Do[t = Plus @@ Select[Divisors@n, # < Sqrt@n &]; If[t > s, AppendTo[lst, n]; s = t], {n, 100000}]; lst
CROSSREFS
Cf. A141037.
Sequence in context: A067114 A102711 A235375 * A045619 A028690 A355331
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Aug 03 2008
STATUS
approved