Your job is as an administrative assistant for factory operations for a company producing Whatchamacallits. Your boss hands you the information that the factory produces 3 Whatchas in the first hour, 7 total after hour 2, 11 total after 3 hours and 15 after 4 hours. You are tasked to produce an equation that models the number of Whatchas produced given the hours worked, and to find the predicted number of Whatchas produced if the factory can run for 50 hour uninterrupted. Find an explicit formula for the nth term of the sequence 3,7,11,15... and use the equation to find the 50th term in the sequence. Show your reasoning for the equation.