The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 22 |
| 4 | 245 |
| 5 | 3576 |
| 6 | 65527 |
| 7 | 1449904 |
| 8 | 37596393 |
| 9 | 1118442880 |
| 10 | 37559084651 |
| 11 | 1405597826304 |
| 12 | 58012540741597 |
| 13 | 2617923512200192 |
| 14 | 128240561732097375 |
| 15 | 6777245042104293376 |
| 16 | 384358793388984148433 |
| 17 | 23284761629109883600896 |
| 18 | 1500714780345430134323923 |
[1,1,3,22,245,3576,65527,1449904,37596393, 1118442880,37559084651,1405597826304, 58012540741597,2617923512200192, 128240561732097375,6777245042104293376, 384358793388984148433,23284761629109883600896, 1500714780345430134323923] |