A088008 - OEIS

%I #11 Feb 22 2023 08:59:07

%S 1,2,4,6,8,10,16,20,28,32,64,70,88,104,110,128,136,152,256,315,464,

%T 496,512,592,650,836,884,1012,1024,1155,1696,1758,1842,1866,1878,1888,

%U 1902,1952,1986,2022,2048,2082,2094,2118,2144,2154,2202,2238,2272,2274,2298

%N 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.

%H Amiram Eldar, <a href="/A088008/b088008.txt">Table of n, a(n) for n = 1..10000</a>

%t abu[x_] := Abs[DivisorSigma[1, x]-2*x] Do[If[ !Greater[abu[n], n^(1/3)//N], Print[n]], {n, 1, 100000}]

%t Select[Range[2300],Abs[DivisorSigma[1,#]-2#]<=CubeRoot[#]&] (* _Harvey P. Dale_, Feb 22 2023 *)

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

%K nonn

%O 1,2

%A _Labos Elemer_, Oct 20 2003