A088008 Solutions to sigma(x) - 2x <= x^(1/3), both even and odd. Abundance-radius = abs(sigma(n)-2n) does not exceed 3rd root of n.

1, 2, 4, 6, 8, 10, 16, 20, 28, 32, 64, 70, 88, 104, 110, 128, 136, 152, 256, 315, 464, 496, 512, 592, 650, 836, 884, 1012, 1024, 1155, 1696, 1758, 1842, 1866, 1878, 1888, 1902, 1952, 1986, 2022, 2048, 2082, 2094, 2118, 2144, 2154, 2202, 2238, 2272, 2274, 2298

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

abu[x_] := Abs[DivisorSigma[1, x]-2*x] Do[If[ !Greater[abu[n], n^(1/3)//N], Print[n]], {n, 1, 100000}]
Select[Range[2300], Abs[DivisorSigma[1, #]-2#]<=CubeRoot[#]&] (* Harvey P. Dale, Feb 22 2023 *)

Crossrefs

Cf. A077374, A088007-A088012, A000396, A000079, A005100, A005101.

Sequence in context: A302299 A227992 A175299 * A067720 A078106 A353764

Adjacent sequences: A088005 A088006 A088007 * A088009 A088010 A088011

Keyword

nonn

Author

Labos Elemer, Oct 20 2003

Status

approved