Pull Numbers That Have Not Been Drawn

Here is the code that I am working with. I want to randomly draw numbers and I want to keep doing this until all the numbers 1:18 have been drawn. I do not want to draw the same number twice.

RandomArray <- sample(1:18, 6, replace=F)

RandomArray2 <- sample(1:18,6, replace = F)
RandomArray3 <- sample(1:18,6, replace = F)
RandomArray2 <- ifelse(RandomArray==RandomArray2,
  sample(1:18,6,replace=F),RandomArray2)

RandomArray3 <- ifelse(RandomArray2==RandomArray3,
            sample(1:18,6,replace=F),RandomArray3)

The ideal output would be

RandomArray [1 2 3 4 5 6] RandomArray2 [7 8 9 10 11 12] RandomArray3 [13 14 15 16 17 18] 

I have also tried doing

x <- 1:18 
test2 <- sapply(x, function(x) 
  if (x == RandomArray) x-RandomArray else x)

But that is not right either because I just want to rid of the numbers I have already drawn.

Thank you for your help.