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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 30 |
| 4 | 344 |
| 5 | 5370 |
| 6 | 106452 |
| 7 | 2562182 |
| 8 | 72592816 |
| 9 | 2367054450 |
| 10 | 87320153900 |
| 11 | 3595646533182 |
| 12 | 163492924997448 |
| 13 | 8136172620013802 |
| 14 | 439858024910227588 |
| 15 | 25670670464821310070 |
| 16 | 1608575860476990991712 |
| 17 | 107716675117341985862370 |
[1,4,30,344,5370,106452,2562182,72592816, 2367054450,87320153900,3595646533182, 163492924997448,8136172620013802, 439858024910227588,25670670464821310070, 1608575860476990991712,107716675117341985862370] |