The population of mosquitoes in a certain area increases at a rate proportional to the current population, and in the absence of other factors, the population doubles each week. There are 600,000 mosquitoes in the area initially, and predators (birds, bats, and so forth) eat 50,000 mosquitoes/day. Determine the population of mosquitoes in the area at any time. (Note that the variable t represents days.) Enter an exact answer. Enclose arguments of functions in parentheses. For example, sin(2x).