arrangement

This code will generate and display all possible arrangements of the numbers 1,2,3:

Imports System
Imports System.Collections.Generic

Module Permutations

  Sub Main()
    Dim perms As New List(Of Integer())

    For i As Integer = 1 To 3               
       For j As Integer =  1 To 3
          If i = j Then Continue For
          For k As Integer = 1 To 3
             If k <> i AndAlso k <> j Then
                perms.Add(New Integer(2){i,j,k})
             End If
          Next k          
       Next j
    Next i

    Console.WriteLine("All possible arrangements of {1,2,3} are:")
    Console.WriteLine()

    For Each perm As Integer() in perms
       Console.Write("{")
       For i As Integer = 0 To 2
           Console.Write(perm(i))
           If i < 2 Then Console.Write(",")
       Next i
       Console.WriteLine("}")
    Next perm           

  End Sub
 
End Module

However, as this sounds like homework, you'll have to do the general case of 'n' numbers yourself to get some benefit from this. To avoid having 'n' For statements, I'd look for a recursive solution.