A054740 Cototient(n)/totient(n) when this is an integer.

0, 1, 1, 2, 1, 2, 1, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset: 1

Author

Labos Elemer, Apr 26 2000

Keywords

• nonn

Comments

EulerPhi of x divides x (A007694) if and only if EulerPhi divides x-EulerPhi. This quotient is smaller by 1 than A049237.

Examples

			x=2592, Phi[2592]=864, Cototient[x]=2592-864=1728 and the quotients are as follows: x/Phi=2592/864=3 or Cototient[x]/Phi[x]=1728/864=2; x always has a form of 2^u*3^w
		

References

• Sárközy A. and Suranyi J., Number Theory Problem Book (in Hungarian)

Crossrefs

A000010, A049237, A007694, A051953.

Programs

Mathematica

Select[(#-EulerPhi[#])/EulerPhi[#]&/@Range[300000],IntegerQ] (* Harvey P. Dale, Mar 01 2015 *)

Formula

A051953[A007694(n)]/A000010[A007694(n)] = A049237(n)-1