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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 102 |
| 4 | 2970 |
| 5 | 16450 |
| 6 | 997220 |
| 7 | 18268740 |
| 8 | 37403100 |
| 9 | 2539082700 |
| 10 | 23305436 |
| 11 | 141249408300 |
| 12 | 97836438700 |
[1,5,102,2970,16450,997220,18268740,37403100, 2539082700,23305436,141249408300,97836438700] |