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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 6 |
| 4 | 30 |
| 5 | 284 |
| 6 | 2344 |
| 7 | 31632 |
| 8 | 492432 |
| 9 | 12098624 |
| 10 | 236007424 |
| 11 | 6065647616 |
| 12 | 159458086912 |
| 13 | 6086725226496 |
| 14 | 260007588237312 |
[1,1,6,30,284,2344,31632,492432,12098624, 236007424,6065647616,159458086912,6086725226496, 260007588237312] |