The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 0 |
| 5 | 30 |
| 6 | 120 |
| 7 | 945 |
| 8 | 7392 |
| 9 | 66780 |
| 10 | 667440 |
| 11 | 7342335 |
| 12 | 88107360 |
| 13 | 1145396538 |
| 14 | 16035550440 |
| 15 | 240533257965 |
| 16 | 3848532125760 |
| 17 | 65425046139960 |
| 18 | 1177650830516832 |
| 19 | 22375365779822715 |
| 20 | 447507315596450880 |
| 21 | 9397653627525472470 |
| 22 | 206748379805560389720 |
| 23 | 4755212735527888968873 |
[0,0,3,0,30,120,945,7392,66780,667440,7342335, 88107360,1145396538,16035550440,240533257965, 3848532125760,65425046139960,1177650830516832, 22375365779822715,447507315596450880, 9397653627525472470,206748379805560389720, 4755212735527888968873] |