A225175 - OEIS

A225175

Largest number which requires n iterations of the bi-unitary totient function (A116550) to reach 1.

1, 2, 3, 6, 10, 11, 12, 18, 30, 42, 78, 106, 210, 366, 550, 603, 750, 1290, 2562, 4398, 4305, 7470, 9090, 14322, 24558, 35382, 55482, 78020, 141190, 207519, 301642, 429870, 552693, 684846, 1060710, 1391390, 2385246, 3454044

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

a(26) >= 55482. a(27) >= 78020. - R. J. Mathar, May 05 2013

REFERENCES

M. Lal, H. Wareham and R. Mifflin, Iterates of the bi-unitary totient function, Utilitas Math., 10 (1976), 347-350.

LINKS

Table of n, a(n) for n=0..37.

CROSSREFS

Cf. A116550, A005424, A225176, A225174, A047994, A003271, A225172, A225173.

Sequence in context: A028255 A342766 A048633 * A286954 A047402 A088196

Adjacent sequences: A225172 A225173 A225174 * A225176 A225177 A225178

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, May 01 2013

EXTENSIONS

a(26)-a(37) from Donovan Johnson, Dec 07 2013

STATUS

approved