The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | -3 |
| 3 | -1 |
| 4 | 2 |
| 5 | -1 |
| 6 | -1 |
| 7 | -1 |
| 8 | -1 |
| 9 | -1 |
| 10 | 1 |
| 11 | 1 |
| 12 | 1 |
| 13 | 1 |
| 14 | -1 |
| 15 | -1 |
| 16 | -1 |
| 17 | -1 |
| 18 | 1 |
| 19 | 1 |
| 20 | 5 |
| 21 | 5 |
[1,1,-3,-1,2,-1,-1,-1,-1,-1,1,1,1,1,-1,-1,-1,-1,1, 1,5,5] |