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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 45 |
| 4 | 450 |
| 5 | 4500 |
| 6 | 45000 |
| 7 | 450000 |
| 8 | 4500000 |
| 9 | 45000000 |
| 10 | 450000000 |
| 11 | 4500000000 |
| 12 | 45000000000 |
| 13 | 450000000000 |
| 14 | 4500000000000 |
| 15 | 45000000000000 |
| 16 | 450000000000000 |
| 17 | 4500000000000000 |
| 18 | 45000000000000000 |
| 19 | 450000000000000000 |
| 20 | 4500000000000000000 |
| 21 | 45000000000000000000 |
| 22 | 450000000000000000000 |
[1,4,45,450,4500,45000,450000,4500000,45000000, 450000000,4500000000,45000000000,450000000000, 4500000000000,45000000000000,450000000000000, 4500000000000000,45000000000000000, 450000000000000000,4500000000000000000, 45000000000000000000,450000000000000000000] |