The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 56 |
| 4 | 616 |
| 5 | 9856 |
| 6 | 216832 |
| 7 | 6288128 |
| 8 | 232660736 |
| 9 | 10702393856 |
| 10 | 599334055936 |
| 11 | 40155381747712 |
| 12 | 3172275158069248 |
| 13 | 291849314542370816 |
| 14 | 30936027341491306496 |
| 15 | 3743259308320448086016 |
| 16 | 512826525239901387784192 |
| 17 | 78975284886944813718765568 |
| 18 | 13583749000554507959627677696 |
| 19 | 2594496059105911020288886439936 |
[1,2,8,56,616,9856,216832,6288128,232660736, 10702393856,599334055936,40155381747712, 3172275158069248,291849314542370816, 30936027341491306496,3743259308320448086016, 512826525239901387784192, 78975284886944813718765568, 13583749000554507959627677696, 2594496059105911020288886439936] |