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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.
5
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
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 *)
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 20 2003
STATUS
approved