This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A110079 #9 Aug 14 2013 16:00:26
%S A110079 5,38,284,1370,2168,26828,133088,1515608,19414448,23521328,25812848,
%T A110079 49353008,82988756,103575728,537394688,558504608,921747488,2651596448,
%U A110079 17517611968,18249863488,77792665408,556915822208
%N A110079 Numbers n such that sigma(n)=2n-2^d(n) where d(n) is number of positive divisors of n.
%C A110079 If 4^m+2^m-1 is prime then n=2^(m-1)*(4^m+2^m-1) is in the sequence because 2n-2^d(n)=2^m*(4^m+2^m-1)-2^(m*2)=2^m* (4^m-1)=2^m*(2^m-1)*(2^m+1)=(2^m-1)*(4^m+2^m)=sigma(2^(m-1)) *sigma(4^m+2^m-1)=sigma(2^(m-1)*(4^m+2^m-1))=sigma(n). A110082 gives such terms of this sequence.
%C A110079 a(22) <= 556915822208. a(23) <= 9311639470208. a(24) <= 29297682437888. - _Donovan Johnson_, Jan 31 2009
%C A110079 a(23) > 6*10^12. - _Giovanni Resta_, Aug 14 2013
%t A110079 Do[If[DivisorSigma[1, n] == 2n - 2^DivisorSigma[0, n], Print[n]], {n, 925000000}]
%Y A110079 Cf. A110080-3.
%K A110079 more,nonn
%O A110079 1,1
%A A110079 _Farideh Firoozbakht_, Aug 03 2005
%E A110079 a(18)-a(21) from _Donovan Johnson_, Jan 31 2009
%E A110079 a(22) confirmed by _Giovanni Resta_, Aug 14 2013