The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 0 |
| 4 | -3 |
| 5 | -12 |
| 6 | -27 |
| 7 | 248 |
| 8 | 2425 |
| 9 | -3504 |
| 10 | -143031 |
| 11 | -115904 |
| 12 | 8956533 |
| 13 | 17130688 |
| 14 | -618394579 |
| 15 | -265254272 |
| 16 | 46232494321 |
| 17 | -452604387072 |
| 18 | -3608163168111 |
| 19 | 186145181366272 |
| 20 | 254307747662573 |
| 21 | -61549828575435776 |
| 22 | 15725973912655477 |
[1,1,1,0,-3,-12,-27,248,2425,-3504,-143031, -115904,8956533,17130688,-618394579,-265254272, 46232494321,-452604387072,-3608163168111, 186145181366272,254307747662573, -61549828575435776,15725973912655477] |