The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 1 |
| 11 | 2 |
| 12 | 7 |
| 13 | 22 |
| 14 | 75 |
| 15 | 239 |
| 16 | 762 |
| 17 | 2385 |
| 18 | 7441 |
[0,0,0,0,0,0,0,0,0,1,2,7,22,75,239,762,2385,7441] |