Pencils of rays
Problem 372Published on Saturday, 18th February 2012, 01:00 pm; Solved by 267; Difficulty rating: 60%
Let R(M, N) be the number of lattice points (x, y) which satisfy M<x≤N, M<y≤N and is odd.
We can verify that R(0, 100) = 3019 and R(100, 10000) = 29750422.
Find R(2·106, 109).
Note: represents the floor function.