| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 4 |
| 7 | 9 |
| 8 | 20 |
| 9 | 41 |
| 10 | 89 |
| 11 | 196 |
| 12 | 443 |
| 13 | 987 |
| 14 | 2246 |
| 15 | 5114 |
| 16 | 11757 |
| 17 | 27122 |
| 18 | 62898 |
| 19 | 146392 |
| 20 | 342204 |
| 21 | 802429 |
| 22 | 1887882 |
[1,1,1,1,3,4,9,20,41,89,196,443,987,2246,5114, 11757,27122,62898,146392,342204,802429,1887882] |