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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 258 |
| 3 | 2607 |
| 4 | 23156 |
| 5 | 193573 |
| 6 | 1552272 |
| 7 | 12111209 |
| 8 | 92571436 |
| 9 | 696659613 |
| 10 | 5178525870 |
| 11 | 38112289517 |
| 12 | 278191828634 |
| 13 | 2016589831189 |
| 14 | 14532118028260 |
| 15 | 104191269908219 |
| 16 | 743719988895596 |
| 17 | 5288057396240333 |
| 18 | 37470071363668612 |
| 19 | 264689231027772351 |
[20,258,2607,23156,193573,1552272,12111209, 92571436,696659613,5178525870,38112289517, 278191828634,2016589831189,14532118028260, 104191269908219,743719988895596,5288057396240333, 37470071363668612,264689231027772351] |