The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 65 |
| 3 | 264 |
| 4 | 4289 |
| 5 | 17420 |
| 6 | 283009 |
| 7 | 1149456 |
| 8 | 18674305 |
| 9 | 75846676 |
| 10 | 1232221121 |
| 11 | 5004731160 |
| 12 | 81307919681 |
| 13 | 330236409884 |
| 14 | 5365090477825 |
| 15 | 21790598321184 |
| 16 | 354014663616769 |
| 17 | 1437849252788260 |
| 18 | 23359602708228929 |
| 19 | 94876260085703976 |
| 20 | 1541379764079492545 |
[1,4,65,264,4289,17420,283009,1149456,18674305, 75846676,1232221121,5004731160,81307919681, 330236409884,5365090477825,21790598321184, 354014663616769,1437849252788260, 23359602708228929,94876260085703976, 1541379764079492545] |