The EulerPhi(sigma(EulerPhi))-perfect numbers, where the f-perfect numbers for an arithmetical function f are defined in A066218.
A066228
The EulerPhi(sigma(EulerPhi))-perfect numbers, where the f-perfect numbers for an arithmetical function f are defined in A066218.
Terms
- a(0) =2a(1) =4a(2) =28a(3) =40a(4) =448a(5) =500380
External references
- oeis: A066228