The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 1 |
| 5 | 0 |
| 6 | 6 |
| 7 | 1 |
| 8 | 2 |
| 9 | 0 |
| 10 | 15 |
| 11 | 2 |
| 12 | 2 |
| 13 | 6 |
| 14 | 0 |
| 15 | 40 |
| 16 | 3 |
| 17 | 4 |
| 18 | 6 |
| 19 | 15 |
| 20 | 0 |
| 21 | 104 |
| 22 | 5 |
| 23 | 6 |
| 24 | 12 |
| 25 | 15 |
| 26 | 40 |
| 27 | 0 |
| 28 | 273 |
[1,0,2,1,0,6,1,2,0,15,2,2,6,0,40,3,4,6,15,0,104,5, 6,12,15,40,0,273] |