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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 187 |
| 5 | 2491 |
| 6 | 41951 |
| 7 | 855387 |
| 8 | 20491395 |
| 9 | 564179371 |
| 10 | 17555839639 |
| 11 | 609337562923 |
| 12 | 23340215770235 |
| 13 | 978038556122811 |
| 14 | 44506423393073487 |
| 15 | 2185725954288076987 |
| 16 | 115224508775345033779 |
| 17 | 6490005347933921581195 |
| 18 | 388973650645651854960455 |
[1,1,3,19,187,2491,41951,855387,20491395, 564179371,17555839639,609337562923,23340215770235, 978038556122811,44506423393073487, 2185725954288076987,115224508775345033779, 6490005347933921581195,388973650645651854960455] |