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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 44 |
| 5 | 222 |
| 6 | 1337 |
| 7 | 9360 |
| 8 | 74880 |
| 9 | 673925 |
| 10 | 6739256 |
| 11 | 74131823 |
| 12 | 889581881 |
| 13 | 11564564464 |
| 14 | 161903902509 |
| 15 | 2428558537649 |
| 16 | 38856936602385 |
| 17 | 660567922240547 |
| 18 | 11890222600329856 |
| 19 | 225914229406267264 |
| 20 | 4518284588125345296 |
[1,3,11,44,222,1337,9360,74880,673925,6739256, 74131823,889581881,11564564464,161903902509, 2428558537649,38856936602385,660567922240547, 11890222600329856,225914229406267264, 4518284588125345296] |