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A069166 Numbers n such that n*sum(d|n,1/sigma(d)) is an integer. 0

%I

%S 1,6,14,40,120,244,280,440,494,680,920,1220,2040,2840,2968,3480,6360,

%T 9880,10680,16376,20618,25160,32280,34720,40136,40280,42136,45560,

%U 45994,46280,85880,91160,120408

%N Numbers n such that n*sum(d|n,1/sigma(d)) is an integer.

%t Select[Range[125000],IntegerQ[# Total[1/DivisorSigma[1,Divisors[#]]]]&] (* _Harvey P. Dale_, Nov 03 2017 *)

%K easy,nonn

%O 1,2

%A _Benoit Cloitre_, Apr 09 2002

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Last modified March 20 09:48 EDT 2019. Contains 321345 sequences. (Running on oeis4.)