The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 3 |
| 5 | 2 |
| 6 | 4 |
| 7 | 2 |
| 8 | 7 |
| 9 | 3 |
| 10 | 14 |
| 11 | 6 |
| 12 | 44 |
| 13 | 37 |
| 14 | 350 |
| 15 | 1616 |
| 16 | 18042 |
| 17 | 193919 |
| 18 | 2867779 |
| 19 | 32674078 |
| 20 | 1581632332 |
| 21 | 6705889886 |
[1,1,2,1,3,2,4,2,7,3,14,6,44,37,350,1616,18042, 193919,2867779,32674078,1581632332,6705889886] |