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%I #25 Dec 15 2017 17:35:35
%S 300,72504,157344,1470456,3454944,7438656,8583168,10097920,32175072,
%T 1519507968,1699447296,8450553312
%N q(n) = sigma(n) - n, where q(n) = n + e(n) + e(n-e(n)) and e(n) = n - eulerphi(n).
%t F[n_] := Abs[EulerPhi[n] - n]; Q[n_] := n+F[n]+F[n-F[n]]; Do[If[Q[n] == DivisorSigma[1, n] - n, Print[n]], {n, 10^9}] (* _Ryan Propper_, Jan 01 2007 *)
%o (PARI) e(n) = n - eulerphi(n);
%o q(n) = n+e(n)+e(n-e(n));
%o for(n=1,10^8, if(q(n)==sigma(n)-n,print1(n, ", ")))
%Y Cf. A051953 (n - eulerphi(n)).
%K more,nonn
%O 1,1
%A _Jason Earls_, Aug 31 2001
%E One more term from _Ryan Propper_, Jan 01 2007
%E a(10)-a(12) from _Lars Blomberg_, Oct 27 2015
%E Offset corrected by _Altug Alkan_, Oct 31 2015
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