The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 173 |
| 4 | 1211969509 |
| 5 | 5547480986860602794895774677 |
| 6 | 708720364531529518355420122993246286974247836241724513772950684967495246261 |
[0,0,1,173,1211969509, 5547480986860602794895774677, 70872036453152951835542012299324628697424783624172\ 4513772950684967495246261] |