| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 22 |
| 3 | 63 |
| 4 | 135 |
| 5 | 555 |
| 6 | 1301 |
| 7 | 4607 |
| 8 | 15441 |
| 9 | 33852 |
| 10 | 240488 |
| 11 | 694409 |
| 12 | 857993 |
| 13 | 5563724 |
| 14 | 9289707 |
| 15 | 28048931 |
| 16 | 129440103 |
| 17 | 262527982 |
| 18 | 1982424660 |
| 19 | 8858170624 |
| 20 | 17601613331 |
[3,22,63,135,555,1301,4607,15441,33852,240488, 694409,857993,5563724,9289707,28048931,129440103, 262527982,1982424660,8858170624,17601613331] |