Need to protect formula but allow input

I was wondering how you can protect a formula but still allow editing in the cell. Right now I have certain columns locked while allowing others to be edited. I have a formula in one column that needs to be edited if need be but if they make a mistake and hit delete then my formula disappears and it throws the whole sheet off. Is there a way to protect your formula maybe by putting it in a different cell that can be locked and referencing the cell where they can input?

Thanks