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.

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

Amiram Eldar, Table of n, a(n) for n = 1..250

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

Adjacent sequences: A141403 A141404 A141405 * A141407 A141408 A141409

Keyword

nonn

Author

Robert G. Wilson v, Aug 03 2008

Status

approved