The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -8 |
| 3 | 44 |
| 4 | -192 |
| 5 | 718 |
| 6 | -2400 |
| 7 | 7352 |
| 8 | -20992 |
| 9 | 56549 |
| 10 | -145008 |
| 11 | 356388 |
| 12 | -844032 |
| 13 | 1934534 |
| 14 | -4306368 |
| 15 | 9337704 |
| 16 | -19771392 |
| 17 | 40965362 |
| 18 | -83207976 |
| 19 | 165944732 |
| 20 | -325393024 |
| 21 | 628092832 |
| 22 | -1194744096 |
| 23 | 2241688744 |
| 24 | -4152367104 |
| 25 | 7599231223 |
| 26 | -13749863984 |
[0,1,-8,44,-192,718,-2400,7352,-20992,56549, -145008,356388,-844032,1934534,-4306368,9337704, -19771392,40965362,-83207976,165944732,-325393024, 628092832,-1194744096,2241688744,-4152367104, 7599231223,-13749863984] |