If you mean produce a sequence of numbers where no number is repeated, like 3, 1, 9, 5, 2, 4, ... then sure, it's very easy:
is there anyway I can generate a random number only once and do not have it repeat.
1. generate an array [0, 1, 2, 3, 4, ... as much as you need, pretty much put the numbers you want in there]
2. for each element A in the array...
----> select a random element B in the array
----> swap elements A and B
3. iterate through the modified array to get your repeat-free random numbers
See Fisher-Yates shuffle. Is this what you meant?