A238228 Numbers n such that if x=sigma(n)+phi(n)-tau(n)-n then n=sigma(x)+phi(x)-tau(x)-x.

12, 14, 27, 125, 127

Offset: 1

Author

Paolo P. Lava, Feb 20 2014

Keywords

• nonn
• more

Comments

a(6) > 2*10^11, if it exists. - Giovanni Resta, Apr 10 2019

Examples

			Fixed points: 27,...
sigma(12) = 28, phi(12) = 4, tau(12) = 6 and 28 + 4 - 6 - 12 = 14.
sigma(14) = 24, phi(14) = 6, tau(14) = 4 and 24 + 6 - 4 - 14 = 12.
		

Crossrefs

Cf. A000005, A000010, A000203, A238225-A238227, A238229, A238230.

Programs

Maple

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