A225173 Number of numbers which require n iterations of the unitary totient function (A047994) to reach 1.

1, 1, 2, 4, 9, 21, 38, 82, 164, 261, 424, 749, 1097, 1721, 2592, 4351, 7319, 10725, 17013, 27773, 44767, 73914, 118990, 185059, 275055, 401059, 617679, 935331, 1379826, 2089569, 2962015, 3899417, 5202824

Offset

0,3

Links

Table of n, a(n) for n=0..32.

M. Lal, Iterates of the unitary totient function, Math. Comp., 28 (1974), 301-302.

Crossrefs

Cf. A047994, A003271, A225172.

Sequence in context: A370315 A034750 A079060 * A346737 A030039 A018105

Adjacent sequences: A225170 A225171 A225172 * A225174 A225175 A225176

Keyword

nonn,more

Author

N. J. A. Sloane, May 01 2013

Extensions

a(16)-a(32) from Donovan Johnson, May 02 2013

Status

approved