%I #8 Jun 02 2022 20:39:03
%S 2,2,2,1,1,3,3,2,1,3,3,2,2,4,6,5,5,4,4,3,5,7,7,6,5,7,6,5,5,5,5,4,6,8,
%T 10,9,9,11,13,12,12,12,12,11,10,12,12,11,10,9,11,10,10,9,11,10,12,14,
%U 14,13,13,15,14,13,15,15,15,14,16,16,16,15,15,17,16,15,17,17,17,16,15
%N sum[k=1 to n] mu(k)+sqf(k): mu(k) is Moebius function; sqf(k)=1 if k is squarefree, sqf(k)=-1 otherwise.
%t Accumulate[Table[MoebiusMu[n]+If[SquareFreeQ[n],1,-1],{n,100}]] (* _Harvey P. Dale_, Jun 02 2022 *)
%K easy,nonn
%O 1,1
%A _Zak Seidov_, Oct 19 2002