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

Author

N. J. A. Sloane, May 01 2013

Keywords

• nonn
• more

Links

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

Crossrefs

Cf. A047994, A003271, A225172.

Extensions

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