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%I #9 Jan 02 2019 07:25:53
%S 0,1,1,1,1,5,1,1,1,8,1,9,1,10,10,1,1,12,1,13,13,13,1,14,1,15,1,16,1,
%T 29,1,1,19,19,19,19,1,20,20,20,1,40,1,22,22,22,1,23,1,24,24,24,1,25,
%U 25,25,25,25,1,57,1,27,27,1,28,62,1,29,29,65,1,30,1,31
%N Number of positive integers less than n with fewer distinct prime factors than n.
%e Column n lists the a(n) positive integers less than n with fewer distinct prime factors than n:
%e 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
%e ---------------------------------------------------------------------
%e 1 1 1 1 5 1 1 1 9 1 11 1 13 13 1 1 17 1 19
%e 4 8 9 11 11 16 17
%e 3 7 8 9 9 13 16
%e 2 5 7 8 8 11 13
%e 1 4 5 7 7 9 11
%e 3 4 5 5 8 9
%e 2 3 4 4 7 8
%e 1 2 3 3 5 7
%e 1 2 2 4 5
%e 1 1 3 4
%e 2 3
%e 1 2
%e 1
%t Table[Length[Select[Range[n],PrimeNu[#]<PrimeNu[n]&]],{n,100}]
%Y Positions of 1's are A246655.
%Y Cf. A000010, A001221, A006049, A067003, A294277, A294278, A302242, A322838, A322841.
%K nonn
%O 1,6
%A _Gus Wiseman_, Dec 28 2018
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