The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -2 |
| 2 | 2 |
| 3 | 2 |
| 4 | -10 |
| 5 | 6 |
| 6 | 42 |
| 7 | -102 |
| 8 | -82 |
| 9 | 782 |
| 10 | -814 |
| 11 | -3854 |
| 12 | 12454 |
| 13 | 5014 |
| 14 | -98694 |
| 15 | 142218 |
| 16 | 472158 |
| 17 | -1932258 |
| 18 | -19038 |
| 19 | 14816994 |
| 20 | -27370410 |
| 21 | -64159962 |
| 22 | 334154442 |
| 23 | -121279878 |
| 24 | -2418497010 |
| 25 | 5523511086 |
| 26 | 8914677362 |
| 27 | -61259567662 |
| 28 | 44249714438 |
[1,-2,2,2,-10,6,42,-102,-82,782,-814,-3854,12454, 5014,-98694,142218,472158,-1932258,-19038, 14816994,-27370410,-64159962,334154442,-121279878, -2418497010,5523511086,8914677362,-61259567662, 44249714438] |