I can do that one manually, but I'm not sure how to convert it to a formula:
2d6 (6*6 = 36 outcomes)
Roll - resistance = damage / # of outcomes
2 - 7 = 0 / 1 -- (1/1)
3 - 7 = 0 / 2 -- (1/2, 2/1)
4 - 7 = 0 / 3 -- (1/3, 3/1, 2/2)
5 - 7 = 0 / 4 -- (1/4, 4/1, 2/3, 3/2)
6 - 7 = 0 / 5 -- (1/5, 5/1...