The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 44 |
| 4 | 312 |
| 5 | 2776 |
| 6 | 30312 |
| 7 | 397728 |
| 8 | 6151768 |
| 9 | 110306160 |
| 10 | 2260463464 |
| 11 | 52304514912 |
| 12 | 1352534122104 |
| 13 | 38742215685776 |
| 14 | 1219910431007656 |
| 15 | 41945588389187712 |
| 16 | 1565744883592488856 |
| 17 | 63123204175617586000 |
[1,2,8,44,312,2776,30312,397728,6151768,110306160, 2260463464,52304514912,1352534122104, 38742215685776,1219910431007656,41945588389187712, 1565744883592488856,63123204175617586000] |