Dim M.i(1000)

M(1)=1
For n=2 To 1000
  psum=0
  For k=2 To n : psum+M(Int(n/k)) : Next : M(n)=1-psum
  If M(n)=0 : z+1 : If M(n-1)<>0 : c+1 : EndIf : EndIf
Next

OpenConsole("")
PrintN("First 99 Mertens numbers:") : Print(Space(4))
For n=1 To 99 : Print(RSet(Str(M(n)),4)) : If n%10=9 : PrintN("") : EndIf : Next
PrintN("M(N) is zero "+Str(z)+" times.") : PrintN("M(N) crosses zero "+Str(c)+" times.")
Input()