| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 14 |
| 5 | 85 |
| 6 | 598 |
| 7 | 4837 |
| 8 | 41570 |
| 9 | 372830 |
| 10 | 3436289 |
| 11 | 32373742 |
| 12 | 310407548 |
| 13 | 3020894755 |
| 14 | 29776585115 |
| 15 | 296777846799 |
| 16 | 2986882651510 |
| 17 | 30321553394791 |
[1,1,4,14,85,598,4837,41570,372830,3436289, 32373742,310407548,3020894755,29776585115, 296777846799,2986882651510,30321553394791] |