OFFSET
1,8
FORMULA
a(n) = n * Sum_{i=1..n} (1 - mu(i)^2), where mu is the Möbius function (A008683).
MATHEMATICA
Table[n*Sum[(1 - MoebiusMu[k]^2), {k, Floor[n/2]}], {n, 80}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Oct 25 2017
STATUS
approved