OFFSET
1,8
FORMULA
a(n) = Sum_{i=1..floor(n/2)} (n - i) * (1 - mu(i)^2), where mu is the Möbius function (A008683).
MATHEMATICA
Table[Sum[(n - k) (1 - MoebiusMu[k]^2), {k, Floor[n/2]}], {n, 80}]
Table[Total[Select[IntegerPartitions[n, {2}], !SquareFreeQ[#[[2]]]&][[All, 1]]], {n, 60}] (* Harvey P. Dale, Jun 20 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Oct 25 2017
STATUS
approved