The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 0 |
| 4 | -12 |
| 5 | -45 |
| 6 | -65 |
| 7 | 1400 |
| 8 | 12096 |
| 9 | 52269 |
| 10 | -469307 |
| 11 | -8565656 |
| 12 | -73323052 |
| 13 | 223125903 |
| 14 | 11882866931 |
| 15 | 176275489312 |
| 16 | 328262199968 |
| 17 | -26579607201031 |
| 18 | -672646430878551 |
| 19 | -4665154122148880 |
| 20 | 76898559105113236 |
| 21 | 3784100596619704043 |
[0,1,1,0,-12,-45,-65,1400,12096,52269,-469307, -8565656,-73323052,223125903,11882866931, 176275489312,328262199968,-26579607201031, -672646430878551,-4665154122148880, 76898559105113236,3784100596619704043] |