| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 39 |
| 6 | 189 |
| 7 | 1107 |
| 8 | 7281 |
| 9 | 54351 |
| 10 | 448821 |
| 11 | 4085883 |
| 12 | 40533129 |
| 13 | 435847959 |
| 14 | 5045745069 |
| 15 | 62594829027 |
| 16 | 828229153761 |
| 17 | 11644113200031 |
| 18 | 173331882039141 |
| 19 | 2723549731505163 |
| 20 | 45047085512477049 |
| 21 | 782326996336904679 |
| 22 | 14233537708408467549 |
| 23 | 270733989894887810547 |
[1,1,1,3,9,39,189,1107,7281,54351,448821,4085883, 40533129,435847959,5045745069,62594829027, 828229153761,11644113200031,173331882039141, 2723549731505163,45047085512477049, 782326996336904679,14233537708408467549, 270733989894887810547] |