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A087415
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Solutions to sigma[x]-2x<=sqrt[x],x is odd. Abundance-radius = Abs[sigma[n]-2n] does not exceed square root of n and n is odd.
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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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MATHEMATICA
| abu[x_] := Abs[DivisorSigma[1, x]-2*x] Do[If[ !Greater[abu[n], Sqrt[n]//N]&& OddQ[n], Print[n]], {n, 1, 100000}]
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CROSSREFS
| Cf. A077374, A088007-A088012, A000396, A000079, A005100, A005101.
Sequence in context: A076773 A114807 A109130 * A184477 A184469 A088010
Adjacent sequences: A087412 A087413 A087414 * A087416 A087417 A087418
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 20 2003
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