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| n | a(n) |
|---|---|
| 1 | 336 |
| 2 | 2740 |
| 3 | 17129 |
| 4 | 89429 |
| 5 | 410718 |
| 6 | 1716324 |
| 7 | 6678657 |
| 8 | 24601591 |
| 9 | 86829924 |
| 10 | 296316228 |
| 11 | 984577369 |
| 12 | 3202676417 |
| 13 | 10242533906 |
| 14 | 32315864964 |
| 15 | 100861744449 |
| 16 | 312101151267 |
| 17 | 959163561400 |
| 18 | 2931830099988 |
| 19 | 8923446044937 |
| 20 | 27069106904461 |
| 21 | 81899632621478 |
[336,2740,17129,89429,410718,1716324,6678657, 24601591,86829924,296316228,984577369,3202676417, 10242533906,32315864964,100861744449,312101151267, 959163561400,2931830099988,8923446044937, 27069106904461,81899632621478] |