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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 40 |
| 6 | 168 |
| 7 | 764 |
| 8 | 3589 |
| 9 | 17460 |
| 10 | 86858 |
| 11 | 440507 |
| 12 | 2267491 |
| 13 | 11819232 |
| 14 | 62250491 |
| 15 | 330794053 |
| 16 | 1771283115 |
| 17 | 9547905381 |
[1,1,3,10,40,168,764,3589,17460,86858,440507, 2267491,11819232,62250491,330794053,1771283115, 9547905381] |