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%I #11 Apr 20 2022 13:36:01
%S 2,1,3,2,1,2,1,1,4,1,2,1,1,3,2,1,3,2,1,5,1,1,1,2,1,1,3,1,2,2,1,4,2,1,
%T 1,2,1,1,3,1,1,2,1,2,6,1,1,2,1,1,3,1,1,2,1,1,4,4,1,2,1,1,1,3,1,1,2,1,
%U 1,1,5,1,2,2,1,3,1,1,2,1,1,4,1,1,2,2,1,1,3,2,1,1,2,3,1,7,1,1,2,1,1,3,3,1,2
%N The count of smallest prime factors in n-th composite.
%e a(1)=2 (4 = 2*2);
%e a(2)=1 (6 = 2*3);
%e a(3)=3 (8 = 2*2*2);
%e a(4)=2 (9 = 3*3).
%p A020639 := proc(n) numtheory[factorset](n) ; min(op(%)) ; end proc:
%p A166948 := proc(n) c := A002808(n) ; smpr := A020639(c) ; for p in ifactors(c)[2] do if op(1,p) = smpr then return op(2,p) ; end if; end do: end proc:
%p seq(A166948(n),n=1..120) ; # _R. J. Mathar_, May 21 2010
%t FactorInteger[#][[1,2]]&/@Select[Range[200],CompositeQ] (* _Harvey P. Dale_, Apr 20 2022 *)
%Y Cf. A002808, A020639.
%K nonn
%O 1,1
%A _Juri-Stepan Gerasimov_, Oct 25 2009
%E Entries checked by _R. J. Mathar_, May 21 2010
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