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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 30 |
| 3 | 300 |
| 4 | 3570 |
| 5 | 64680 |
| 6 | 1231230 |
| 7 | 29609580 |
| 8 | 746876130 |
| 9 | 22309287000 |
| 10 | 834590426670 |
| 11 | 32089678420800 |
| 12 | 1461885412557570 |
| 13 | 72411562719475980 |
| 14 | 3676255934199278430 |
| 15 | 201683848689025182480 |
| 16 | 12416469379809407042130 |
[4,30,300,3570,64680,1231230,29609580,746876130, 22309287000,834590426670,32089678420800, 1461885412557570,72411562719475980, 3676255934199278430,201683848689025182480, 12416469379809407042130] |