The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 36 |
| 3 | 696 |
| 4 | 2250 |
| 5 | 14712 |
| 6 | 245508 |
| 7 | 737352 |
| 8 | 3644355 |
| 9 | 17376832 |
| 10 | 325225824 |
| 11 | 823612736 |
| 12 | 3820113552 |
| 13 | 14264475648 |
| 14 | 66782014272 |
| 15 | 1254553664640 |
| 16 | 2949123559125 |
| 17 | 12008271483720 |
| 18 | 41150373332932 |
| 19 | 157262062899640 |
| 20 | 608878151760410 |
| 21 | 12804954311547288 |
| 22 | 27181470392583156 |
[1,8,36,696,2250,14712,245508,737352,3644355, 17376832,325225824,823612736,3820113552, 14264475648,66782014272,1254553664640, 2949123559125,12008271483720,41150373332932, 157262062899640,608878151760410,12804954311547288, 27181470392583156] |