The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 120 |
| 6 | 0 |
| 7 | 2520 |
| 8 | 0 |
| 9 | 120960 |
| 10 | 25401600 |
| 11 | 9979200 |
| 12 | 3832012800 |
| 13 | 1245404160 |
| 14 | 719220902400 |
| 15 | 91755151488000 |
| 16 | 174356582400000 |
| 17 | 45045272143872000 |
| 18 | 53602095414067200 |
| 19 | 21303098209096704000 |
| 20 | 2012983121565351936000 |
| 21 | 11213752210271170560000 |
| 22 | 2291193190664226680832000 |
[1,0,0,0,0,120,0,2520,0,120960,25401600,9979200, 3832012800,1245404160,719220902400,91755151488000, 174356582400000,45045272143872000, 53602095414067200,21303098209096704000, 2012983121565351936000,11213752210271170560000, 2291193190664226680832000] |