A039773 phi(n) is equal to the sum of prime factors and exponents of n-1.

5, 34, 66, 130, 490, 18130

Offset: 1

Author

Olivier Gérard

Keywords

• nonn

Examples

			phi(34)=16, 33=3^1*11^1, 3+1+11+1=16.
		

Crossrefs

Cf. A000010, A008474.

Programs

Mathematica

Select[Range[20000],Total[Flatten[FactorInteger[#-1]]]==EulerPhi[#]&] (* Harvey P. Dale, Mar 27 2017 *)

Extensions

Next term if it exists is >= 5*10^7 - Naohiro Nomoto, Jun 24 2001.