OFFSET
1,4
FORMULA
a(n) = Sum_{i=2..floor(n/2)} (n - i) * mu(i)^2, where mu is the Möbius function (A008683).
MATHEMATICA
Table[Sum[(n - i) MoebiusMu[i]^2, {i, 2, Floor[n/2]}], {n, 80}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Oct 26 2017
STATUS
approved