| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 10 |
| 5 | 22 |
| 6 | 108 |
| 7 | 544 |
| 8 | 3370 |
| 9 | 24030 |
| 10 | 195172 |
| 11 | 1777648 |
| 12 | 17950554 |
| 13 | 199059670 |
| 14 | 2405063020 |
| 15 | 31448531952 |
| 16 | 442501797658 |
| 17 | 6666753146494 |
| 18 | 107081325959940 |
| 19 | 1826636018849440 |
[1,10,22,108,544,3370,24030,195172,1777648, 17950554,199059670,2405063020,31448531952, 442501797658,6666753146494,107081325959940, 1826636018849440] |
