| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 23 |
| 4 | 383 |
| 5 | 8456 |
| 6 | 228657 |
| 7 | 7268077 |
| 8 | 264627570 |
| 9 | 10842464809 |
| 10 | 493454895161 |
| 11 | 24695915073150 |
| 12 | 1348165575801780 |
| 13 | 79740451015249487 |
| 14 | 5080946666286668723 |
| 15 | 347046897108675507548 |
| 16 | 25300042941361404342404 |
| 17 | 1960975025091063811051791 |
| 18 | 161045636717926154800016147 |
| 19 | 13970534533583992498224467231 |
[1,1,2,23,383,8456,228657,7268077,264627570, 10842464809,493454895161,24695915073150, 1348165575801780,79740451015249487, 5080946666286668723,347046897108675507548, 25300042941361404342404,1960975025091063811051791, 161045636717926154800016147, 13970534533583992498224467231] |