The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | -2 |
| 4 | 4 |
| 5 | -12 |
| 6 | 36 |
| 7 | -140 |
| 8 | 519 |
| 9 | -2632 |
| 10 | 11776 |
| 11 | -82020 |
| 12 | 426990 |
| 13 | -4149112 |
| 14 | 22719260 |
| 15 | -309921456 |
| 16 | 1487214652 |
| 17 | -31477804596 |
| 18 | 82495148888 |
| 19 | -4227929653508 |
| 20 | -7155535440434 |
| 21 | -767565126075852 |
| 22 | -6245080462329816 |
| 23 | -194907866415800464 |
[1,-2,4,-12,36,-140,519,-2632,11776,-82020,426990, -4149112,22719260,-309921456,1487214652, -31477804596,82495148888,-4227929653508, -7155535440434,-767565126075852,-6245080462329816, -194907866415800464] |