Prove that for every positive integer n, there is a sequence of integers a0,a1,…,a2009 with a_0\equal{}0 and a_{2009}\equal{}n such that each term after a0 is either an earlier term plus 2k for some nonnnegative integer k, or of the form bmodc for some earlier positive terms b and c. [Here bmodc denotes the remainder when b is divided by c, so 0≤(bmodc)<c.] Putnaminductioncollege contests