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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 22 |
| 5 | 71 |
| 6 | 319 |
| 7 | 1939 |
| 8 | 19790 |
| 9 | 377259 |
| 10 | 14603435 |
| 11 | 1144417513 |
| 12 | 176665721300 |
| 13 | 52525450429119 |
| 14 | 29719386740326525 |
| 15 | 31836493683553082697 |
| 16 | 64474640381705842520802 |
| 17 | 246962703426353769596309789 |
| 18 | 1791765285568042699367722904797 |
| 19 | 24670014908867411635732865067513309 |
[1,1,3,7,22,71,319,1939,19790,377259,14603435, 1144417513,176665721300,52525450429119, 29719386740326525,31836493683553082697, 64474640381705842520802, 246962703426353769596309789, 1791765285568042699367722904797, 24670014908867411635732865067513309] |