A238231 Numbers n such that if x=phi(n)*tau(n)-sigma(n)-n then n=phi(x)*tau(x)-sigma(x)-x.

376, 594, 846, 1178, 1222, 46498, 65198

Offset: 1

Author

Paolo P. Lava, Feb 20 2014

Keywords

• nonn
• more

Comments

a(8) > 2*10^9. - Giovanni Resta, Mar 26 2014

Examples

			Fixed points: 376,...
phi(594) = 180, tau(594) = 16, sigma(594) = 1440 and 180*16 - 1440 - 594 = 846.
phi(846) = 276, tau(846) = 12, sigma(846) = 1872 and 276*12 - 1872 - 846 = 594.
		

Crossrefs

Cf. A000005, A000010, A000203, A238225-A238230.

Programs

Maple

with(numtheory); P:=proc(q)local a,n;
for n from 1 to q do a:=phi(n)*tau(n)-sigma(n)-n;
if a>0 and phi(a)*tau(a)-sigma(a)-a=n then print(n);
fi; od; end: P(10^6);