The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | -2 |
| 2 | -4 |
| 3 | -20 |
| 4 | -252 |
| 5 | -5610 |
| 6 | -187944 |
| 7 | -8760272 |
| 8 | -540315160 |
| 9 | -42535905530 |
| 10 | -4158250120140 |
| 11 | -493938370048692 |
| 12 | -70043599065844404 |
| 13 | -11684931733886455730 |
| 14 | -2264985487707963662992 |
| 15 | -504752888883221450120000 |
| 16 | -128137017404994234514023024 |
[0,-2,-4,-20,-252,-5610,-187944,-8760272, -540315160,-42535905530,-4158250120140, -493938370048692,-70043599065844404, -11684931733886455730,-2264985487707963662992, -504752888883221450120000, -128137017404994234514023024] |