A372706 - OEIS

%I #9 May 11 2024 09:41:20

%S 1,-1,0,0,1,0,1,0,0,-1,1,0,2,-3,-2,0,1,0,2,0,-4,-3,1,0,0,-4,0,0,1,6,3,

%T 0,-5,-5,-3,0,1,-5,-3,0,0,9,2,0,0,-6,2,0,0,0,-5,0,2,0,-5,0,-5,-5,0,0,

%U 1,-7,0,0,-4,12,1,0,-5,10,2,0,3,-8,0,0,-4,14,3,0,0,-8,3,0,-7,-8,-5,0,1,0,-4,0

%N a(n) = Sum_{k=1..n} mu(n*k), where mu is the Moebius function A008683.

%F If n is not squarefree, a(n) = 0.

%o (PARI) a(n) = sum(k=1, n, moebius(n*k));

%Y Cf. A002321, A008663, A013929, A372700.

%K sign

%O 1,13

%A _Seiichi Manyama_, May 10 2024