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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 120 |
| 3 | 3284 |
| 4 | 91518 |
| 5 | 2545230 |
| 6 | 70894196 |
| 7 | 1973960628 |
| 8 | 54973461294 |
| 9 | 1530909659694 |
| 10 | 42634040850720 |
| 11 | 1187302679649470 |
| 12 | 33064936696401300 |
| 13 | 920817809589881572 |
| 14 | 25643653148853690776 |
| 15 | 714144422751974649034 |
| 16 | 19888051043349007713954 |
[2,120,3284,91518,2545230,70894196,1973960628, 54973461294,1530909659694,42634040850720, 1187302679649470,33064936696401300, 920817809589881572,25643653148853690776, 714144422751974649034,19888051043349007713954] |