Non-repetitive random number

Question

To generate Random numbers from 1- 20 I need to pick selective and it should not be repetitive.

How to do this in C#

Note I need to loop through as like this

Answer 1

blow code generates 65 unique random number between 0 - 92 and return that unique random numbers in an array.

public static int[] RandomNumbers_Supplier()
        {
            Random R = new Random();
            int[] RandomNumbers = new int[65];
            int k = 0, Temp;
            bool IsRepetitive = false;
            while (k < 65)
            {
                Temp = R.Next(0, 92);
                for (int i = 0; i < 65; i++)
                {
                    IsRepetitive = false;
                    if (RandomNumbers[i] == Temp)
                    {
                        IsRepetitive = true;
                        break;
                    }                    
                }
                if (!IsRepetitive)
                {
                    RandomNumbers[k] = Temp;
                    k++;
                }
            }
            return(RandomNumbers)
        }