The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 33 |
| 4 | 216 |
| 5 | 1865 |
| 6 | 21228 |
| 7 | 303765 |
| 8 | 5222864 |
| 9 | 104540337 |
| 10 | 2383558740 |
| 11 | 60933722069 |
| 12 | 1725392415288 |
| 13 | 53590463856345 |
| 14 | 1811281159509500 |
| 15 | 66172416761172885 |
| 16 | 2598298697830360992 |
| 17 | 109116931783034360801 |
| 18 | 4880122696811960470692 |
| 19 | 231565260558289051906965 |
[0,1,6,33,216,1865,21228,303765,5222864,104540337, 2383558740,60933722069,1725392415288, 53590463856345,1811281159509500,66172416761172885, 2598298697830360992,109116931783034360801, 4880122696811960470692,231565260558289051906965] |