The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 20 |
| 2 | 400 |
| 3 | 1862 |
| 4 | 9825 |
| 5 | 53516 |
| 6 | 311642 |
| 7 | 2018993 |
| 8 | 12150635 |
| 9 | 69284509 |
| 10 | 382383387 |
| 11 | 1994236773 |
[1,20,400,1862,9825,53516,311642,2018993,12150635, 69284509,382383387,1994236773] |