| n | a(n) |
|---|---|
| 3 | 4 |
| 4 | 42 |
| 5 | 552 |
| 6 | 13751 |
| 7 | 425674 |
| 8 | 18458342 |
| 9 | 1164072896 |
| 10 | 139921844820 |
| 11 | 38221283215416 |
| 12 | 19223028387830564 |
| 13 | 13952451706754445456 |
[4,42,552,13751,425674,18458342,1164072896, 139921844820,38221283215416,19223028387830564, 13952451706754445456] |