the actual problem here is that I've got 2 questions in my book and for some reason no introduction to these 2 questions was given. The only hint I've got is that they are a part of the "Indices, Growth and Decay" chapter. It would be great if someone could show me how to use the mentioned stuff when solving the problems.

1. How many different sums can you make of 5 cent, 10 cent, 20 cent, 50 cent, 1$ and 2$ coins?

2. Find the sequence of odd numbers using Nicomachus' pattern ( 7 + 9 + 11 = 27 = 3^3 ) for 7^3.