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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 32 |
| 4 | 392 |
| 5 | 6488 |
| 6 | 135360 |
| 7 | 3408120 |
| 8 | 100520432 |
| 9 | 3398723928 |
| 10 | 129588803696 |
| 11 | 5500585388616 |
| 12 | 257232445666832 |
[1,4,32,392,6488,135360,3408120,100520432, 3398723928,129588803696,5500585388616, 257232445666832] |