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A087415
Odd numbers n such that abs(sigma(n)-2n) <= sqrt(n). Abundance-radius = abs(sigma(n)-2n) does not exceed square root of n and n is odd.
1
1, 315, 945, 1155, 2205, 7425, 8415, 8925, 9405, 9555, 24885, 26145, 26325, 28035, 30555, 31815, 32445, 33705, 34335, 35595, 40005, 40365, 41265, 43155, 46035, 49875, 51765, 55335, 78975, 80535, 83265, 91455, 96915, 101475, 106425, 130815, 191565, 338415
OFFSET
1,2
LINKS
MATHEMATICA
abu[x_] := Abs[DivisorSigma[1, x]-2*x] Do[If[ !Greater[abu[n], Sqrt[n]//N]&& OddQ[n], Print[n]], {n, 1, 100000}]
KEYWORD
nonn
AUTHOR
Labos Elemer, Oct 20 2003
STATUS
approved