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A200810
Iterate k -> d(k) until an odd prime is reached.
3
3, 3, 5, 3, 7, 3, 3, 3, 11, 3, 13, 3, 3, 5, 17, 3, 19, 3, 3, 3, 23, 3, 3, 3, 3, 3, 29, 3, 31, 3, 3, 3, 3, 3, 37, 3, 3, 3, 41, 3, 43, 3, 3, 3, 47, 3, 3, 3, 3, 3, 53, 3, 3, 3, 3, 3, 59, 3, 61, 3, 3, 7, 3, 3, 67, 3, 3, 3, 71, 3, 73, 3, 3, 3, 3, 3, 79, 3, 5, 3, 83
OFFSET
3,1
COMMENTS
Csajbók and Kasza call this "lasttau(n)". Imre Kátai asks for its asymptotic behavior.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 3..10000
Tímea Csajbók and János Kasza, Iterating the tau-function, Annales Univ. Sci. Budapest., Sec. Math. 35 (2011), pp. 83-93.
PROG
(PARI) a(n)=while(!isprime(n), n=numdiv(n)); n \\ Charles R Greathouse IV, Nov 23 2011
CROSSREFS
Sequence in context: A015971 A163167 A243729 * A365710 A114003 A219792
KEYWORD
nonn
AUTHOR
STATUS
approved