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Let f(k^n) = m where m is the largest power of k+1 < k^n. a(n) = number of iterations of f to reach 1, starting from n and starting from k = 2.
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%I #3 Mar 31 2012 20:01:48

%S 0,1,2,2,3,4,4,5,5,5,6,6,7,8,8,9,9,9,9,9,10,11,11,12,12,12,12,13,13,

%T 14,14,14,14,14,15,16,16,16,16,17,17,17,18,19,19,19

%N Let f(k^n) = m where m is the largest power of k+1 < k^n. a(n) = number of iterations of f to reach 1, starting from n and starting from k = 2.

%e a(5)=4 as f(2^5)=3^3 < 2^5, f(3^3)=4^2 < 3^3, f(4^2)=5 < 4^2 and f(5)=6^0 < 5.

%K easy,nonn

%O 0,3

%A _Naohiro Nomoto_, Dec 29 2003