The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 0 |
| 3 | 1 |
| 4 | 8 |
| 5 | 15 |
| 6 | 48 |
| 7 | 105 |
| 8 | 384 |
| 9 | 945 |
| 10 | 3840 |
| 11 | 10395 |
| 12 | 46080 |
| 13 | 135135 |
| 14 | 645120 |
| 15 | 2027025 |
| 16 | 10321920 |
| 17 | 34459425 |
| 18 | 185794560 |
| 19 | 654729075 |
| 20 | 3715891200 |
| 21 | 13749310575 |
| 22 | 81749606400 |
| 23 | 316234143225 |
| 24 | 1961990553600 |
| 25 | 7905853580625 |
| 26 | 51011754393600 |
| 27 | 213458046676875 |
| 28 | 1428329123020800 |
[0,1,8,15,48,105,384,945,3840,10395,46080,135135, 645120,2027025,10321920,34459425,185794560, 654729075,3715891200,13749310575,81749606400, 316234143225,1961990553600,7905853580625, 51011754393600,213458046676875,1428329123020800] |