TIMO 2018 Grade 3 Heat Set 4 Question 1

What is the value of the number to represent “?” in the following table?

| First | Second | Third |
|---:|---:|---:|
| 1 | 1 | 1 |
| 2 | 4 | 8 |
| 3 | 9 | 27 |
| 4 | 16 | 64 |
| 5 | 25 | ? |