This doesnt make sense to me. if 1 should be 100, then 2 should be 101, and 3 -> 102 presumably
but your example seems to have 3 -> 103
Is there some special logic to consider ? or do you want to know how to add 99 to all the numbers ?
if you have a dataframe called mydf with a column Episode then (using base R)
mydf$Episode <- mydf$Episode + 99