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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 8 |
| 5 | 38 |
| 6 | 234 |
| 7 | 1679 |
| 8 | 13802 |
| 9 | 127155 |
| 10 | 1297619 |
| 11 | 14516296 |
| 12 | 176640311 |
| 13 | 2322876382 |
| 14 | 32831464503 |
| 15 | 496399943530 |
| 16 | 7995690518504 |
| 17 | 136701790293581 |
| 18 | 2472679442088700 |
| 19 | 47180405307783443 |
| 20 | 947116124382018095 |
| 21 | 19954735355719570880 |
| 22 | 440286840550877179031 |
[1,1,2,8,38,234,1679,13802,127155,1297619, 14516296,176640311,2322876382,32831464503, 496399943530,7995690518504,136701790293581, 2472679442088700,47180405307783443, 947116124382018095,19954735355719570880, 440286840550877179031] |