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%I #9 Jan 06 2020 08:36:13
%S 0,1,1,2,1,1,1,3,2,1,1,1,1,4,1,1,1,1,2,3,1,1,5,1,2,1,1,1,1,2,1,1,1,1,
%T 1,6,1,2,1,1,4,1,1,1,1,2,1,2,1,1,3,1,7,1,1,2,1,1,1,1,1,1,1,1,1,2,2,1,
%U 3,1,2,1,5,1,1,1,8,1,1,2,1,1,1,1,2,1,3,1,1,1,1,1,2,2,1,1,3,2,1,1
%N Minimal exponent in prime factorization of 7-smooth numbers.
%H Amiram Eldar, <a href="/A086290/b086290.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A051904(A002473(n)).
%F a(n) <= A086291(n) <= A086289(n).
%t minExp[1] = 0; minExp[n_] := Min @@ Last /@ FactorInteger[n]; minExp/@Select[Range[500], Max[Transpose[FactorInteger[#]][[1]]] <= 7 &] (* _Amiram Eldar_, Jan 06 2020 *)
%Y Cf. A002473, A051904, A086289, A086291.
%K nonn
%O 1,4
%A _Reinhard Zumkeller_, Jul 15 2003
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