Which point lies on the graph of the finite sequence

The correct answer is (6,-1)

For any point P that is not exactly one of the points in your graph, the probability that P lies on the graph is exactly 0.There are literally an infinite number of functions that pass exactly through any finite set of given points. There are an infinite number of possible paths between the known points, and there is no mathematical way of saying that any one path is more "right" than the other (not unless there is additional external information about the function.) The probability that the path will happen to pass through any one given point P is 1 divided by infinity, which is 0.You cannot do any better unless you know the exact form of the generating function. For example if you knowthat it is a polynomial of degree 4, then you can do something. If you don't know the right shape of curve then there is nothing you can do.