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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 9 |
| 8 | 19 |
| 9 | 45 |
| 10 | 171 |
| 11 | 795 |
| 12 | 4151 |
| 13 | 23359 |
| 14 | 160489 |
| 15 | 1338097 |
| 16 | 13206661 |
| 17 | 152301919 |
| 18 | 2072243263 |
| 19 | 33494417573 |
| 20 | 640878789973 |
| 21 | 14468834259627 |
| 22 | 385605211468773 |
| 23 | 12154715457880649 |
| 24 | 453340950276092835 |
[1,1,1,1,1,3,9,19,45,171,795,4151,23359,160489, 1338097,13206661,152301919,2072243263,33494417573, 640878789973,14468834259627,385605211468773, 12154715457880649,453340950276092835] |