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A146566
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Numbers k such that k*sigma_0(k) is divisible by (k - sigma_0(k)).
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6
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3, 4, 6, 8, 12, 18, 24, 36, 40, 60, 84, 156, 180, 600
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OFFSET
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1,1
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COMMENTS
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No other term multiple of 12 below 10^9. - M. F. Hasler, Apr 16 2022
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LINKS
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FORMULA
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MATHEMATICA
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nsiQ[n_]:=Module[{s=DivisorSigma[0, n]}, IntegerQ[(n*s)/(n-s)]]; Select[ Range[3, 600], nsiQ] (* Harvey P. Dale, Dec 05 2019 *)
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PROG
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(PARI) isok(n) = {nd = numdiv(n); type(n*nd/(n-nd)) == "t_INT"} \\ Michel Marcus, Jun 02 2013
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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