| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 44 |
| 3 | 1360 |
| 4 | 118864 |
| 5 | 29454720 |
| 6 | 20723316480 |
| 7 | 41430374667264 |
| 8 | 235483137163985920 |
| 9 | 3806579106735674587136 |
| 10 | 175045931960590896961989632 |
| 11 | 22902901668710944230193460535296 |
| 12 | 8527272133354589357030560193109508096 |
[1,4,44,1360,118864,29454720,20723316480, 41430374667264,235483137163985920, 3806579106735674587136, 175045931960590896961989632, 22902901668710944230193460535296, 8527272133354589357030560193109508096] |