Recurrence relation

Recurrence relations are like a circle - you start with one number and then use that number to calculate the next number in the circle. This can keep happening, with the next number always being based on the last. It's a bit like a recipe, where each step in the recipe tells you what you have to do to get to the next step. For example, suppose you want to figure out how many cookies you'd have after 10 days if you started with one cookie and doubled the number of cookies each day. You would start with 1 cookie, then double it to get 2 cookies (1x2=2) and then double again to get 4 cookies (2x2=4), and so on until the 10th day when you'd have 1,024 cookies (2 to the 10th power). This is called a recurrence relation because you're repeating the same operation over and over again to get the answer.