The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 20 |
| 4 | 46 |
| 5 | 310 |
| 6 | 1002 |
| 7 | 4929 |
| 8 | 28917 |
| 9 | 170693 |
| 10 | 1255834 |
| 11 | 10402982 |
| 12 | 92718038 |
[1,7,20,46,310,1002,4929,28917,170693,1255834, 10402982,92718038] |