AT-OEMO-REG 2009 Problem 4

Two infinite arithmetic progressions are called considerable different if the do not only differ by the absence of finitely many members at the beginning of one of the sequences. How many pairwise considerable different non-constant arithmetic progressions of positive integers that contain an infinite non-constant geometric progression $(b_n)_{n\ge0}$ with $b_2=40 \cdot 2009$ are there?