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Total number of prime factors of 7-smooth numbers.
5

%I #10 Jan 06 2020 09:13:55

%S 0,1,1,2,1,2,1,3,2,2,3,2,2,4,3,3,2,4,2,3,3,3,5,2,4,4,3,3,5,2,3,4,4,4,

%T 3,6,3,5,3,5,4,4,4,6,3,4,3,5,5,5,3,4,7,4,4,6,3,4,6,5,5,3,5,4,7,4,5,4,

%U 6,6,4,6,5,3,4,5,8,5,5,7,4,5,4,7,6,6,3,4,6,4,5,8,5,6,5,5,7,4,7,5

%N Total number of prime factors of 7-smooth numbers.

%H Amiram Eldar, <a href="/A086289/b086289.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A001222(A002473(n)).

%F A086290(n) <= A086291(n) <= a(n).

%t PrimeOmega[Select[Range[500], Max[Transpose[FactorInteger[#]][[1]]] <= 7 &]] (* _Amiram Eldar_, Jan 06 2020 after G. C. Greubel at A086288 *)

%Y Cf. A001222, A002473, A086288, A086290, A086291.

%K nonn

%O 1,4

%A _Reinhard Zumkeller_, Jul 15 2003