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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 23 |
| 6 | 81 |
| 7 | 325 |
| 8 | 1429 |
| 9 | 6851 |
| 10 | 35443 |
| 11 | 196507 |
| 12 | 1160633 |
| 13 | 7266561 |
| 14 | 48022313 |
| 15 | 333776331 |
| 16 | 2432140759 |
| 17 | 18528143535 |
| 18 | 147201596073 |
| 19 | 1216952016245 |
| 20 | 10448532393869 |
| 21 | 92999784076875 |
| 22 | 856739848236627 |
| 23 | 8156691628658019 |
| 24 | 80147320081510673 |
| 25 | 811770418508099905 |
[1,1,1,3,7,23,81,325,1429,6851,35443,196507, 1160633,7266561,48022313,333776331,2432140759, 18528143535,147201596073,1216952016245, 10448532393869,92999784076875,856739848236627, 8156691628658019,80147320081510673, 811770418508099905] |