实现上述功能的VB程序如下，但加框处代码有错，请改正。

Private Sub Command1_Click()

  Text2．Text=coding(Text1．Text)

End Sub

Private Function coding(s As String)As String

 Dim n As Integer，i As Integer，C As String

 c=Mid(s，1，1)

n=1

 For i=2 To Len(s)

    If  Then    ‘(1)

       n=n+1

    Else

      c=c+Str(n)+“／”

      n=1

    End If

  Next i

  coding=     ‘(2)

End Function

请在下列程序代码的基础上按照要求设计该程序，完善程序中的划线部分。

Dim n As Integer, a1 As Integer, a2 As Integer, a3 As Integer

Function f(x as integer) As Boolean

 f=True

 For i=2 To Sqr(x)

   If x Mod i=0 Then {#blank#}1{#/blank#}

 Next i

End Function

Private Sub Command1_Click()

n={#blank#}2{#/blank#}

For a1=2 To n

 For a2=a1 To n

  For a3=a2 To n

   If{#blank#}3{#/blank#}And f(a1) And f(a2) And f(a3) Then

    List1.AddItem(Str(a1)+“ ”+Str(a2)+“ ”+Str(a3))

   End If

  Next a3

 Next a2

Next a1

End Sub