In this problem, we are interested in the number of ways we can write an integer involving just the values of 1, 4, and 5. For example, there are 6 ways to write 6: 6 = 1 + 1 + 1 + 1 + 1 + 1 = 1 + 1 + ?
1) 1
2) 4
3) 5
4) 6