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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 145 |
| 4 | 2470 |
| 5 | 46060 |
| 6 | 910252 |
| 7 | 18730855 |
| 8 | 397089550 |
| 9 | 8612835715 |
| 10 | 190223180840 |
| 11 | 4263421511271 |
| 12 | 96723482198980 |
| 13 | 2216905597676000 |
| 14 | 51256802757808320 |
| 15 | 1194060413809070710 |
| 16 | 27999654303202465310 |
| 17 | 660370070571422998410 |
| 18 | 15654733143626084944150 |
[1,1,10,145,2470,46060,910252,18730855,397089550, 8612835715,190223180840,4263421511271, 96723482198980,2216905597676000,51256802757808320, 1194060413809070710,27999654303202465310, 660370070571422998410,15654733143626084944150] |