| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 204 |
| 3 | 4152 |
| 4 | 90012 |
| 5 | 1916640 |
| 6 | 41086080 |
| 7 | 878480688 |
| 8 | 18801691584 |
| 9 | 402251873664 |
| 10 | 8607198763968 |
| 11 | 184162678606848 |
| 12 | 3940493249544192 |
| 13 | 84313290894281472 |
| 14 | 1804026190433055744 |
| 15 | 38600161433802577920 |
| 16 | 825915469757893794816 |
| 17 | 17671849531462458580992 |
[6,204,4152,90012,1916640,41086080,878480688, 18801691584,402251873664,8607198763968, 184162678606848,3940493249544192, 84313290894281472,1804026190433055744, 38600161433802577920,825915469757893794816, 17671849531462458580992] |