%I A110817
%S A110817 1,2,9,135,32895,2147516415
%N A110817 Numbers n such that (1/n)sigma(n+1) is an integer.
%C A110817 These are all the terms up to 10^8.
%e A110817 sigma(2+1)/2 = 2, so 2 is a term of the sequence.
%t A110817 Select[Range[10^6], IntegerQ[DivisorSigma[1, # + 1]/# ] &]
%Y A110817 Sequence in context: A047684 A162955 A064448 this_sequence A110860 A050995 
               A117116
%Y A110817 Adjacent sequences: A110814 A110815 A110816 this_sequence A110818 A110819 
               A110820
%K A110817 nonn,new
%O A110817 1,2
%A A110817 Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Sep 15 2005
%E A110817 a(6) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 15 2009