A369865 - OEIS

%I #8 Jun 26 2024 22:12:37

%S 0,1,1,2,1,5,1,0,3,7,1,6,1,9,8,0,1,6,1,10,10,13,1,0,5,15,0,14,1,31,1,

%T 0,14,19,12,0,1,21,16,0,1,41,1,22,15,25,1,0,7,10,20,26,1,0,16,0,22,31,

%U 1,30,1,33,21,0,18,61,1,34,26,59,1,0,1,39,15,38,18,71,1

%N a(n) = n * Sum_{p|n, p prime} mu(n/p)^2 / p.

%F a(p^k) = p^(k-1) for p prime and 1 <= k <= 2, else 0 if k >= 3. - _Wesley Ivan Hurt_, Jun 26 2024

%t Table[n*DivisorSum[n, (MoebiusMu[n/#]^2)/# &, PrimeQ[#] &], {n, 100}]

%Y Cf. A008683, A143519, A369742, A369864.

%K nonn,easy

%O 1,4

%A _Wesley Ivan Hurt_, Feb 03 2024