|
%I #8 Sep 10 2019 09:57:40
%S 24,1536,1631,47360,82458
%N z(sigma(n)) = 2n, where z(n) = A048146.
%o (PARI) u(n) = sumdiv(n,d, if(gcd(d,n/d)==1,d));
%o z(n) = sigma(n)-u(n);
%o for(n=1,10^7, if(z(sigma(n))==2*n,print1(n, ", ")))
%Y Cf. A000203, A034448, A048146, A019284.
%K nonn,more
%O 1,1
%A _Jason Earls_, Aug 28 2001
|
