The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 8 |
| 6 | 73 |
| 7 | 672 |
| 8 | 6770 |
| 9 | 73600 |
| 10 | 867569 |
| 11 | 11029248 |
| 12 | 150742645 |
| 13 | 2205811712 |
| 14 | 34431907210 |
| 15 | 571334098944 |
| 16 | 10045455007565 |
| 17 | 186604618153984 |
| 18 | 3652428217290821 |
| 19 | 75141207379476480 |
| 20 | 1621181018271308650 |
| 21 | 36605039847171424256 |
| 22 | 863329965706545148957 |
| 23 | 21231158030664753217536 |
[0,0,0,0,1,8,73,672,6770,73600,867569,11029248, 150742645,2205811712,34431907210,571334098944, 10045455007565,186604618153984,3652428217290821, 75141207379476480,1621181018271308650, 36605039847171424256,863329965706545148957, 21231158030664753217536] |