In R, you can do it using the `rep`command:

    tab <- data.frame(value=c(1, 2, 3, 4, 5), freq=c(2, 1, 4, 2, 1))
    vec <- rep(tab$value, tab$freq)

This gives following result:

    > tab
      value freq
    1     1    2
    2     2    1
    3     3    4
    4     4    2
    5     5    1
    
    > vec
     [1] 1 1 2 3 3 3 3 4 4 5

For details, see the help file for the `rep`command by typing `?rep`.