The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 24 |
| 4 | 324 |
| 5 | 5120 |
| 6 | 93750 |
| 7 | 1959552 |
| 8 | 46118408 |
| 9 | 1207959552 |
| 10 | 34867844010 |
| 11 | 1100000000000 |
| 12 | 37661140520652 |
| 13 | 1390911669927936 |
| 14 | 55123269399790046 |
| 15 | 2333521433367183360 |
| 16 | 105094533691406250000 |
| 17 | 5017514388048998039552 |
| 18 | 253135520137219049838162 |
| 19 | 13456471561751415850795008 |
[0,0,2,24,324,5120,93750,1959552,46118408, 1207959552,34867844010,1100000000000, 37661140520652,1390911669927936,55123269399790046, 2333521433367183360,105094533691406250000, 5017514388048998039552,253135520137219049838162, 13456471561751415850795008] |