| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 2 |
| 5 | 16 |
| 6 | 134 |
| 7 | 1164 |
| 8 | 10982 |
| 9 | 112354 |
| 10 | 1245676 |
| 11 | 14909340 |
| 12 | 191916532 |
| 13 | 2646100822 |
| 14 | 38932850396 |
| 15 | 609137502242 |
| 16 | 10101955358506 |
| 17 | 177053463254274 |
| 18 | 3270694371428814 |
| 19 | 63524155236581118 |
| 20 | 1294248082658393546 |
| 21 | 27604013493657933856 |
| 22 | 615135860462018980316 |
[0,0,0,2,16,134,1164,10982,112354,1245676, 14909340,191916532,2646100822,38932850396, 609137502242,10101955358506,177053463254274, 3270694371428814,63524155236581118, 1294248082658393546,27604013493657933856, 615135860462018980316] |