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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 16 |
| 3 | 1520 |
| 4 | 495180 |
| 5 | 433646850 |
| 6 | 611015783700 |
| 7 | 1736467679089500 |
| 8 | 9462444875350395600 |
[1,16,1520,495180,433646850,611015783700, 1736467679089500,9462444875350395600] |