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%I #8 Jan 29 2020 04:38:48
%S 0,1,1,2,1,3,2,1,4,1,1,3,5,2,1,1,6,2,4,1,2,7,2,1,1,3,5,8,2,2,1,3,1,9,
%T 2,3,6,1,3,2,10,2,4,1,1,3,3,11,7,2,4,2,1,3,4,12,1,2,4,3,1,8,3,5,13,2,
%U 2,4,4,1,1,3,5,14,3,2,9,4,5,1,2,3,5,15,4,2,1,4,6,1,3,3,10,5,16,5,2,2
%N Minimal exponent in prime factorization of 3-smooth numbers.
%H Amiram Eldar, <a href="/A086414/b086414.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A051904(A003586(n));
%F a(n) <= A086415(n) <= A069352(n).
%t s = {}; m = 12; Do[n = 3^k; While[n <= 3^m, AppendTo[s, n]; n*=2], {k, 0, m}]; maxExp[1] = 0; maxExp[n_] := Min @@ Last /@ FactorInteger[n]; maxExp /@ Union[s] (* _Amiram Eldar_, Jan 29 2020 *)
%Y Cf. A003586, A051904, A069352, A086415.
%K nonn
%O 1,4
%A _Reinhard Zumkeller_, Jul 18 2003