Efficient unique random numbers

Hello all,

I am attempting to assign a random number from 1 - 20 to 20 different variables. I need each variable to have a unique number. I later put the variables in a list and because of the randomly generated numbers the list is in a different order everytime the program is run. What i have works, but i feel it is bulky. I was wondering if there was a more efficient way of achieving this. Thanks:

Here is an exerpt of how i am proceeding, this shows the process for the first 10 variables, but the last 10 follow the same pattern:

n1= Math.floor(Math.random()*20)+1;

questionRandomizer1 ();

questionRandomizer2 ();

questionRandomizer3 ();

questionRandomizer4 ();

questionRandomizer5 ();

questionRandomizer6 ();

questionRandomizer7 ();

questionRandomizer8 ();

questionRandomizer9 ();

questionRandomizer10 ();

questionRandomizer11 ();

questionRandomizer12 ();

questionRandomizer13 ();

questionRandomizer14 ();

questionRandomizer15 ();

questionRandomizer16 ();

questionRandomizer17 ();

questionRandomizer18 ();

questionRandomizer19 ();

questionRandomizer20 ();

function questionRandomizer1 ()

{

          QuestionOrder[1] = n1;

}

function questionRandomizer2 ()

{

          QuestionOrder[2] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[2] == QuestionOrder[1]){questionRandomizer2 ()}        

}

//I am generating a random number for QuestionOrder[2] then checking if it is the same number as QuestionOrder[1] and if it is, i am re-running the function to generate a new random number, until it gets a unique number. This pattern continues for each following function.

function questionRandomizer3 ()

{

          QuestionOrder[3] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[3] == QuestionOrder[1] || QuestionOrder[3] == QuestionOrder[2]){questionRandomizer3 ()}

}

function questionRandomizer4 ()

{

          QuestionOrder[4] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[4] == QuestionOrder[1] || QuestionOrder[4] == QuestionOrder[2]|| QuestionOrder[4] == QuestionOrder[3]){questionRandomizer4 ()}

}

function questionRandomizer5 ()

{

          QuestionOrder[5] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[5] == QuestionOrder[1] || QuestionOrder[5] == QuestionOrder[2]|| QuestionOrder[5] == QuestionOrder[3]|| QuestionOrder[5] == QuestionOrder[4]){questionRandomizer5 ()}

}

function questionRandomizer6 ()

{

          QuestionOrder[6] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[6] == QuestionOrder[1] || QuestionOrder[6] == QuestionOrder[2]|| QuestionOrder[6] == QuestionOrder[3]|| QuestionOrder[6] == QuestionOrder[4]

                    || QuestionOrder[6] == QuestionOrder[5]){questionRandomizer6 ()}

}

function questionRandomizer7 ()

{

          QuestionOrder[7] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[7] == QuestionOrder[1] || QuestionOrder[7] == QuestionOrder[2]|| QuestionOrder[7] == QuestionOrder[3]|| QuestionOrder[7] == QuestionOrder[4]

                    || QuestionOrder[7] == QuestionOrder[5] || QuestionOrder[7] == QuestionOrder[6]){questionRandomizer7 ()}

}

function questionRandomizer8 ()

{

          QuestionOrder[8] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[8] == QuestionOrder[1] || QuestionOrder[8] == QuestionOrder[2]|| QuestionOrder[8] == QuestionOrder[3]|| QuestionOrder[8] == QuestionOrder[4]

                    || QuestionOrder[8] == QuestionOrder[5] || QuestionOrder[8] == QuestionOrder[6] || QuestionOrder[8] == QuestionOrder[7]){questionRandomizer8 ()}

}

function questionRandomizer9 ()

{

          QuestionOrder[9] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[9] == QuestionOrder[1] || QuestionOrder[9] == QuestionOrder[2]|| QuestionOrder[9] == QuestionOrder[3]|| QuestionOrder[9] == QuestionOrder[4]

                    || QuestionOrder[9] == QuestionOrder[5] || QuestionOrder[9] == QuestionOrder[6] || QuestionOrder[9] == QuestionOrder[7] || QuestionOrder[9] == QuestionOrder[8]){questionRandomizer9 ()}

}

function questionRandomizer10 ()

{

          QuestionOrder[10] = Math.floor(Math.random()*20)+1;

          if (QuestionOrder[10] == QuestionOrder[1] || QuestionOrder[10] == QuestionOrder[2]|| QuestionOrder[10] == QuestionOrder[3]|| QuestionOrder[10] == QuestionOrder[4]

                    || QuestionOrder[10] == QuestionOrder[5] || QuestionOrder[10] == QuestionOrder[6] || QuestionOrder[10] == QuestionOrder[7] || QuestionOrder[10] == QuestionOrder[8]

                    || QuestionOrder[10] == QuestionOrder[9]){questionRandomizer10 ()}

}

as you can see the list of checks gets progressively longer. I feel like i am doing a ton of If, Then, Else statements, and usually when that happens i'll use a case system. Im wondering if there is a more efficient way to do this, in the same way a case statement is more efficient than a bunch of If, Then, Else statements.

Thanks.