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Exponent of 3 (value of i) in n-th number of form 3^i*8^j.
1

%I #13 Jun 11 2015 03:13:30

%S 0,1,0,2,1,3,0,2,4,1,3,5,0,2,4,6,1,3,5,7,0,2,4,6,8,1,3,5,7,9,0,2,4,6,

%T 8,10,1,3,5,7,9,11,0,2,4,6,8,10,12,1,3,5,7,9,11,13,0,2,4,6,8,10,12,14,

%U 1,3,5,7,9,11,13,15,0,2,4,6,8,10,12,14,16,1,3,5,7,9,11,13,15,17,0,2,4,6,8,10

%N Exponent of 3 (value of i) in n-th number of form 3^i*8^j.

%H Robert Israel, <a href="/A025643/b025643.txt">Table of n, a(n) for n = 1..10000</a>

%p N:= 10^40: # include entries for all 3^i*8^j <= N

%p map(t -> t[1],sort([seq(seq([i,j],j=0..floor(log[8](N/3^i))),i=0..floor(log[3](N)))],(s,t) -> 3^s[1]*8^s[2]<=3^t[1]*8^t[2]));

%Y Cf. A025615, A025672.

%K nonn

%O 1,4

%A _David W. Wilson_