The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 3 |
| 5 | 12 |
| 6 | 136 |
| 7 | 204 |
| 8 | 1437 |
| 9 | 3520 |
| 10 | 20700 |
| 11 | 31956 |
| 12 | 317513 |
| 13 | 390364 |
| 14 | 2973536 |
| 15 | 8504720 |
| 16 | 32471391 |
| 17 | 61276740 |
| 18 | 622088400 |
| 19 | 790198476 |
| 20 | 6798297447 |
| 21 | 17290258088 |
| 22 | 79394956608 |
| 23 | 138325216092 |
| 24 | 1460955482487 |
[0,0,0,3,12,136,204,1437,3520,20700,31956,317513, 390364,2973536,8504720,32471391,61276740, 622088400,790198476,6798297447,17290258088, 79394956608,138325216092,1460955482487] |