The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 15 |
| 4 | 224 |
| 5 | 5665 |
| 6 | 215136 |
| 7 | 11466903 |
| 8 | 815542272 |
| 9 | 74626924833 |
| 10 | 8539305740800 |
| 11 | 1194616544819423 |
| 12 | 200588161750990848 |
| 13 | 39810821495648979009 |
| 14 | 9219256372209251966976 |
| 15 | 2463653490073311266825895 |
| 16 | 752468103154551980520636416 |
| 17 | 260483894045203867466646001345 |
[1,1,2,15,224,5665,215136,11466903,815542272, 74626924833,8539305740800,1194616544819423, 200588161750990848,39810821495648979009, 9219256372209251966976,2463653490073311266825895, 752468103154551980520636416, 260483894045203867466646001345] |