Answer:
A(3) = 13
A(4) = 18
A(10) = 48
Explanation:
This seems like a plug and play.
Starting with A(3). Everywhere you see an n, you'll replace it with a 3, as follows;
3 + (3-1)(5) = ?
We'll solve it step by step. First is 3-1. That's 2, bringing it to
3 + (2)(5).
2 times 5 is 10, bringing it to
3 + 10.
3 + 10 = 13, which concludes
A(3) = 13.
Now doing it for the remaining 2.
3 + (4-1)(5)
3 + (3)(5)
3 + 15
A(4) = 18
Last one...
3 + (10-1)(5)
3 + (9)(5)
3 + 45
A(10) = 48