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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 420 |
| 3 | 4620 |
| 4 | 13860 |
| 5 | 106260 |
| 6 | 367080 |
| 7 | 1021020 |
| 8 | 1741740 |
| 9 | 1492260 |
| 10 | 5290740 |
| 11 | 38198160 |
| 12 | 42222180 |
| 13 | 29609580 |
| 14 | 19399380 |
| 15 | 23483460 |
| 16 | 66186120 |
[4,420,4620,13860,106260,367080,1021020,1741740, 1492260,5290740,38198160,42222180,29609580, 19399380,23483460,66186120] |