A077083 Length of iteration until a fixed point is reached when phi(sigma[n]+phi(n)) = A077080(n) is iterated with initial value of n.

1, 1, 2, 2, 3, 1, 2, 16, 16, 1, 2, 16, 17, 17, 16, 15, 16, 15, 16, 1, 2, 1, 2, 14, 14, 16, 15, 14, 15, 14, 15, 13, 14, 15, 15, 10, 11, 15, 14, 13, 14, 11, 12, 2, 14, 1, 2, 1, 12, 6, 2, 12, 13, 3, 2, 2, 3, 1, 2, 11, 12, 11, 2, 11, 14, 10, 11, 13, 2, 2, 3, 5, 6, 14, 10, 10, 2, 12, 13, 9

Offset: 1

Author

Labos Elemer, Oct 28 2002

Keywords

• nonn

Examples

			n=1,2,6,10,..864: a[n]=1, n is fixed point for some n; n=225: results in iteration sequence of 44 terms: {225,522,444,...,471744,653312,570240}, 44=a[225].
		

Crossrefs

Cf. A000010, A000203, A065387, A077080-A077085.

Programs

Mathematica

f[x_] := EulerPhi[DivisorSigma[1, x]+EulerPhi[x]] Table[Length[FixedPointList[f, w]]-1, {w, 1, 1024}]

Formula

a(n)=Length[FixedPointList[A077080, n]]-1.