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%I #13 Aug 03 2014 14:37:23
%S 2,854,751358,1421637,8775206,8892195,16485944,31845344,95494035,
%T 277653495,380438505,744048855,1091725394,1615353002,2284844925,
%U 2491028745,6345217034,8490513014,12784909335,14177454885,15669084375,17694356295,17836667354,24180347115
%N Numbers n such that phi(n+1)-phi(n)=sigma(n+1)-sigma(n).
%C This sequence is a subsequence of A066198.
%t de[n_]:=DivisorSigma[1,n]-EulerPhi[n];Do[If[de[n]==de[n+1],Print[n]],{n,50000000}] (* Firoozbakht *)
%t Select[Range[10^6], (EulerPhi[# + 1] - EulerPhi[#]) == (DivisorSigma[1, # + 1] - DivisorSigma[1, #]) &] (* _Alonso del Arte_, Feb 08 2012 *)
%Y Cf. A066198, A145749.
%K nonn
%O 1,1
%A _Farideh Firoozbakht_, Nov 01 2008
%E a(9)-a(16) from _Donovan Johnson_, Dec 14 2009
%E a(17)-a(24) from _Donovan Johnson_, Feb 08 2012