The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 18 |
| 3 | 53 |
| 4 | 148 |
| 5 | 416 |
| 6 | 1144 |
| 7 | 3060 |
| 8 | 7135 |
| 9 | 12959 |
| 10 | 14050 |
| 11 | 4858 |
| 12 | 252 |
[1,6,18,53,148,416,1144,3060,7135,12959,14050, 4858,252] |