Unity3d C ＃ generates non repeated random numbers in the interval

unity3D C# Generate non repeated random numbers in the interval

   private void Start()
    {
        foreach (var item in GetHashtableRandomNum(5, 0, 6).Values)
        {
            Debug.Log(item);
        } 
    }

 

/// <summary>
    ///  Generate random number 
    /// </summary>
    /// <param name="num"> Number of random numbers </param>
    /// <param name="min"> Minimum random number </param>
    /// <param name="max"> Maximum random number </param>
    /// <returns></returns>
    public static Hashtable GetHashtableRandomNum(int num, int min, int max)
    {
        System.Random random = new System.Random();
        Hashtable hashtable = new Hashtable();
        for (int i = 0; hashtable.Count < num; i++)
        {
            int nValue = random.Next(min, max);

            if (!hashtable.ContainsValue(nValue) && nValue != min)
            {
                hashtable.Add(i, nValue);
            }
        }
        return hashtable;
    }