%I #3 Feb 20 2022 22:38:54
%S 1,3,6,10,11,17,24,36,33,34,45,61,58,72,87,115,104,131,123,147,144,
%T 166,189,237,214,215,251,247,244,274,305,365,338,372,407,486,444,482,
%U 521,593,562,604,647,695,701,693,740,852,789,815,791,847,844,952,899,995,956,1014
%N Sum of the numbers <= n that are either squarefree, a divisor of n, or both.
%F a(n) = Sum_{k=1..n} k * sign(mu(k)^2 + 1  ceiling(n/k) + floor(n/k)).
%Y Cf. A008966.
%K nonn
%O 1,2
%A _Wesley Ivan Hurt_, Feb 20 2022
