The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 216 |
| 3 | 24883200000 |
| 4 | 82606411253903523840000000 |
| 5 | 409933016554924328182440935903164918932547530146724293451448320000000000000000000000 |
[4,216,24883200000,82606411253903523840000000, 40993301655492432818244093590316491893254753014672\ 4293451448320000000000000000000000] |