The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 56 |
| 3 | 17550 |
| 4 | 15249024 |
| 5 | 28143753000 |
| 6 | 94689953674560 |
| 7 | 525169893772283760 |
| 8 | 4469844204191484518400 |
| 9 | 55337211594165488805417600 |
| 10 | 955860613004397508326213120000 |
| 11 | 22282564877342299983672172489536000 |
| 12 | 682182070950002359574696677978908672000 |
| 13 | 26812831292465310201469047550286967518976000 |
[1,1,56,17550,15249024,28143753000,94689953674560, 525169893772283760,4469844204191484518400, 55337211594165488805417600, 955860613004397508326213120000, 22282564877342299983672172489536000, 682182070950002359574696677978908672000, 26812831292465310201469047550286967518976000] |