| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 11 |
| 4 | 66 |
| 5 | 146 |
| 6 | 876 |
| 7 | 2131 |
| 8 | 12786 |
| 9 | 32966 |
| 10 | 197796 |
| 11 | 530526 |
| 12 | 3183156 |
| 13 | 8786436 |
| 14 | 52718616 |
| 15 | 148733571 |
| 16 | 892401426 |
| 17 | 2561439806 |
| 18 | 15368638836 |
| 19 | 44731364266 |
| 20 | 268388185596 |
| 21 | 790211926076 |
| 22 | 4741271556456 |
| 23 | 14095578557486 |
[1,1,6,11,66,146,876,2131,12786,32966,197796, 530526,3183156,8786436,52718616,148733571, 892401426,2561439806,15368638836,44731364266, 268388185596,790211926076,4741271556456, 14095578557486] |