A088818 Abundance-radius of n = Abs[sigma[n]-2n]<=log[log[n]].

6, 16, 28, 32, 64, 128, 256, 496, 512, 1024, 1952, 2048, 4096, 8128, 8192, 16384, 32768, 32896, 65536, 130304, 131072, 262144, 522752, 524288, 1048576, 2097152, 4194304, 8382464, 8388608, 16777216, 33550336, 33554432, 67108864, 134193152

Offset

1,1

Links

Table of n, a(n) for n=1..34.

Example

Perfect numbers are here.
It is an infinite sequence since includes A000079,
[as quasiperfect numbers].

Mathematica

abu[x_] := Abs[DivisorSigma[1, x]-2*x] Do[If[ !Greater[abu[n], Log[Log[n]]//N], Print[n]], {n, 1, 1000000}

Crossrefs

Cf. A088009-A088012, A077374, A000396, A000079.

Sequence in context: A320693 A274848 A201020 * A346620 A032422 A164052

Adjacent sequences: A088815 A088816 A088817 * A088819 A088820 A088821

Keyword

nonn

Author

Labos Elemer, Oct 20 2003

Extensions

a(28)-a(34) from Donovan Johnson, Dec 21 2008

Status

approved