The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 0 |
| 6 | 0 |
| 7 | 6 |
| 8 | 24 |
| 9 | 0 |
| 10 | 0 |
| 11 | 139 |
| 12 | 289 |
| 13 | 0 |
| 14 | 0 |
| 15 | 2414 |
| 16 | 4455 |
| 17 | 0 |
| 18 | 0 |
| 19 | 33222 |
| 20 | 63700 |
| 21 | 0 |
| 22 | 0 |
| 23 | 437489 |
| 24 | 794953 |
| 25 | 0 |
| 26 | 0 |
[0,0,1,1,0,0,6,24,0,0,139,289,0,0,2414,4455,0,0, 33222,63700,0,0,437489,794953,0,0] |