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A096996 a(n) is the smallest initial value if function f(x)=sigma(phi(x))=A062402(x) is iterated and the iteration ends in a cycle of length n. 1
1, 5, 17, 401 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(5) exists and <= 2^80.
a(6) = 883, a(11) = 88897, a(15) = 470137, a(18) = 448181;
a(9) = 24877841, a(12) = 16295171, a(21) <= 726569551. 254808457 does not reach a cycle after 14000 iterations. - Hiroaki Yamanouchi, Sep 06 2014
a(5) <= 9248288975491. - Hiroaki Yamanouchi, Sep 10 2014
a(5) > 8.5*10^7. - Tyler Busby, Mar 29 2024
LINKS
EXAMPLE
a(4) = 401. 401 -> 961 -> 2304 -> 2044 -> 2520 -> 1651 -> 4800 -> 3066 -> 2520 (cycle length = 4). - Hiroaki Yamanouchi, Sep 06 2014
CROSSREFS
Sequence in context: A081479 A335313 A318751 * A256236 A070294 A245568
KEYWORD
nonn,hard,more
AUTHOR
Labos Elemer, Jul 19 2004
STATUS
approved

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Last modified May 29 03:48 EDT 2024. Contains 372921 sequences. (Running on oeis4.)