The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 180 |
| 4 | 27720 |
| 5 | 122522400 |
| 6 | 130429015516800 |
| 7 | 1970992304700453905270400 |
| 8 | 1897544233056092162003806758651798777216000 |
| 9 | 4368924363354820808981210203132513655327781713900627249499856876120704000 |
[1,2,12,180,27720,122522400,130429015516800, 1970992304700453905270400, 1897544233056092162003806758651798777216000, 43689243633548208089812102031325136553277817139006\ 27249499856876120704000] |