The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | -1 |
| 5 | 4 |
| 6 | 5 |
| 7 | 7 |
| 8 | 20 |
| 9 | 325 |
| 10 | 104615 |
| 11 | 10943984020 |
| 12 | 119770786197183303365 |
| 13 | 14345041226291394498726932547331126324135 |
| 14 | 205780207783999715270619814569860727079365052973702253248437750317796955577133460 |
[1,2,1,-1,4,5,7,20,325,104615,10943984020, 119770786197183303365, 14345041226291394498726932547331126324135, 20578020778399971527061981456986072707936505297370\ 2253248437750317796955577133460] |