The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 6 |
| 5 | 11 |
| 6 | 56 |
| 7 | 609 |
| 8 | 39346 |
| 9 | 8728237 |
| 10 | 6126648298 |
| 11 | 14487876826313 |
[1,1,2,3,6,11,56,609,39346,8728237,6126648298, 14487876826313] |