So for the birthday paradox, what if you instead wanted to find the probability that any two people in a group of say, five have a birthday *within one day of each other?* When I first thought of this problem I thought you could just calculate it as if there were 15 people in a regular birthday problem since each persons' "range" is triple the size. But if person A has a birthday on 2/1 and person B has a birthday on 2/3, the sum of their "range" extends only five days instead of six. Does anyone know how you could account for this when trying to calculate this?