The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | -1 |
| 8 | -7 |
| 9 | -23 |
| 10 | -59 |
| 11 | -139 |
| 12 | -311 |
| 13 | -677 |
| 14 | -1443 |
| 15 | -3031 |
| 16 | -6295 |
| 17 | -12967 |
| 18 | -26543 |
| 19 | -54073 |
| 20 | -109743 |
| 21 | -222071 |
| 22 | -448323 |
| 23 | -903411 |
| 24 | -1817767 |
| 25 | -3653245 |
| 26 | -7335147 |
| 27 | -14716663 |
| 28 | -29508351 |
| 29 | -59138095 |
| 30 | -118472607 |
[0,1,1,1,1,1,1,-1,-7,-23,-59,-139,-311,-677,-1443, -3031,-6295,-12967,-26543,-54073,-109743,-222071, -448323,-903411,-1817767,-3653245,-7335147, -14716663,-29508351,-59138095,-118472607] |