Search: id:A135239
Results 1-1 of 1 results found.

%I A135239
%S A135239 1209,27474741,55385589,222850677
%N A135239 Numbers n such that sigma(phi(n))=2n.
%C A135239 No other terms below 10^10.
%e A135239 sigma(phi(222850677))=sigma(118879488)=445701354=2*222850677, so 222850677 
               is in the sequence.
%t A135239 Do[If[DivisorSigma[1,EulerPhi[n]]==2n,Print[n]],{n,420000000}]
%Y A135239 Cf. A135240.
%Y A135239 Sequence in context: A156620 A133142 A068534 this_sequence A046043 A138480 
               A047627
%Y A135239 Adjacent sequences: A135236 A135237 A135238 this_sequence A135240 A135241 
               A135242
%K A135239 more,nonn
%O A135239 1,1
%A A135239 Farideh Firoozbakht (mymontain(AT)yahoo.com), Dec 26 2007
%E A135239 Search extended to 10^10 by Max Alekseyev (maxale(AT)gmail.com), Sep 
               25 2009

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