Create random numbers in a column with no repeats

[Nessnc]

I attempting to create a formula that will create random numbers in a column without repeats. For example, I have a spreadsheet with two columns. The first column I want to contain the random numbers and the second column will contain names. I just need the formula to create the random numbers once. I'm sure this is probably fairly easy for some, but not me. Ugh! Thank you for your help.

 

[TheCman81]

How long do the numbers need to be? If it's 6 digits digits you can use the following which will give you almost 1 million chance of there being a duplicate

=RANDBETWEEN(100000,999999)

 

[Nessnc]

It would be starting at 1 and most likely not go past 900