If a Cat has 4 kittens, and in 6 months those kittens have 4 kittens, and so on for 7 years, such that 14 batches of kittens are produced, from the one kitten. I produce the summation: $\sum_{x=1}^{14} 4^x$ Where added up looks like $4 + 16 + 64 + \cdots +4^{14}$.
Is there some kind of trick in maths for working this huge number out without a calculator?