| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 29 |
| 5 | 99 |
| 6 | 355 |
| 7 | 1333 |
| 8 | 5213 |
| 9 | 21163 |
| 10 | 88899 |
| 11 | 385413 |
| 12 | 1720637 |
| 13 | 7894827 |
| 14 | 37166563 |
| 15 | 179254501 |
| 16 | 884548253 |
| 17 | 4460597131 |
| 18 | 22962705027 |
| 19 | 120557527941 |
| 20 | 644952640253 |
| 21 | 3512995320939 |
| 22 | 19468234666531 |
| 23 | 109694091843109 |
| 24 | 628027149163613 |
| 25 | 3651429293510731 |
| 26 | 21547912967252163 |
[1,1,3,9,29,99,355,1333,5213,21163,88899,385413, 1720637,7894827,37166563,179254501,884548253, 4460597131,22962705027,120557527941,644952640253, 3512995320939,19468234666531,109694091843109, 628027149163613,3651429293510731, 21547912967252163] |