The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 9 |
| 2 | -48 |
| 3 | 208 |
| 4 | -816 |
| 5 | 3024 |
| 6 | -10800 |
| 7 | 37584 |
| 8 | -128304 |
| 9 | 431568 |
| 10 | -1434672 |
| 11 | 4723920 |
| 12 | -15431472 |
| 13 | 50073552 |
| 14 | -161558064 |
| 15 | 518686416 |
| 16 | -1658095920 |
| 17 | 5280397776 |
| 18 | -16759523376 |
| 19 | 53033560272 |
| 20 | -167365651248 |
| 21 | 526891865040 |
| 22 | -1655060329008 |
| 23 | 5188335188688 |
| 24 | -16234468171056 |
| 25 | 50711792328144 |
[0,9,-48,208,-816,3024,-10800,37584,-128304, 431568,-1434672,4723920,-15431472,50073552, -161558064,518686416,-1658095920,5280397776, -16759523376,53033560272,-167365651248, 526891865040,-1655060329008,5188335188688, -16234468171056,50711792328144] |