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A225176
Number of numbers which require n iterations of the bi-unitary totient function (A116550) to reach 1.
3
1, 1, 1, 2, 3, 2, 2, 4, 7, 6, 13, 12, 16, 24, 31, 51, 66, 87, 126, 139, 187, 260, 331, 412, 551, 693
OFFSET
1,4
REFERENCES
M. Lal, H. Wareham and R. Mifflin, Iterates of the bi-unitary totient function, Utilitas Math., 10 (1976), 347-350.
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, May 01 2013
STATUS
approved