The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | -1 |
| 3 | -3 |
| 4 | -10 |
| 5 | -10 |
| 6 | -10 |
| 7 | 560 |
| 8 | 1220 |
| 9 | 24936 |
| 10 | -53660 |
| 11 | 1220252 |
| 12 | -13415576 |
| 13 | 140346648 |
| 14 | -2192051992 |
| 15 | 28246127520 |
| 16 | -453007180912 |
| 17 | 7224412576832 |
| 18 | -124772679402064 |
| 19 | 2275818139520912 |
| 20 | -43588354415158432 |
| 21 | 881182228173945952 |
[1,0,-1,-3,-10,-10,-10,560,1220,24936,-53660, 1220252,-13415576,140346648,-2192051992, 28246127520,-453007180912,7224412576832, -124772679402064,2275818139520912, -43588354415158432,881182228173945952] |