OFFSET
1,3
LINKS
FORMULA
a(n) = Sum_{i=1..floor(n/2)} (n - i) * mu(i)^2, where mu is the Möbius function (A008683).
MATHEMATICA
Table[Sum[(n - i)*MoebiusMu[i]^2, {i, Floor[n/2]}], {n, 80}]
Table[Total[Select[IntegerPartitions[n, {2}], SquareFreeQ[#[[2]]]&][[;; , 1]]], {n, 70}] (* Harvey P. Dale, Mar 23 2023 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Oct 23 2017
STATUS
approved