The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 27 |
| 3 | 144 |
| 4 | 648 |
| 5 | 3564 |
| 6 | 15066 |
| 7 | 91368 |
| 8 | 325863 |
| 9 | 2519910 |
| 10 | 5487183 |
| 11 | 80131680 |
| 12 | -19315584 |
| 13 | 3165288840 |
| 14 | -10368295812 |
| 15 | 157258666944 |
| 16 | -910416537216 |
| 17 | 9230359934844 |
| 18 | -66824394346314 |
| 19 | 594882273889656 |
| 20 | -4709265051598938 |
| 21 | 40223940845756976 |
| 22 | -330361209519974280 |
[1,6,27,144,648,3564,15066,91368,325863,2519910, 5487183,80131680,-19315584,3165288840, -10368295812,157258666944,-910416537216, 9230359934844,-66824394346314,594882273889656, -4709265051598938,40223940845756976, -330361209519974280] |