| n | a(n) |
|---|---|
| 1 | 121 |
| 2 | 704 |
| 3 | 4256 |
| 4 | 20398 |
| 5 | 98575 |
| 6 | 397340 |
| 7 | 1623115 |
| 8 | 5744912 |
| 9 | 20612708 |
| 10 | 65877470 |
| 11 | 213190201 |
| 12 | 627225413 |
| 13 | 1867007833 |
| 14 | 5131067959 |
| 15 | 14261504547 |
| 16 | 37041121138 |
| 17 | 97280493869 |
| 18 | 241057367009 |
| 19 | 603912355679 |
| 20 | 1438964930953 |
| 21 | 3465601783227 |
[121,704,4256,20398,98575,397340,1623115,5744912, 20612708,65877470,213190201,627225413,1867007833, 5131067959,14261504547,37041121138,97280493869, 241057367009,603912355679,1438964930953, 3465601783227] |