(*Mathematica 8.0.1*)
(*start*)
(*The program generates the first nn=160 terms of A006530*)
nn = 160;
Monitor[Table[
  1 + n - Sum[
    Sum[N@Cos[-2*Pi*k/n*Product[j^n, {j, 1, m}]]/n, {m, 1, n}], {k, 1,
      n}], {n, 1, nn}], n]
Round[%]
(*end*)