The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 1998 |
| 3 | 722484 |
| 4 | 291762942 |
| 5 | 125454173544 |
| 6 | 56146411655460 |
| 7 | 25832836404319152 |
| 8 | 12128921727745915062 |
| 9 | 5783583949613172902394 |
| 10 | 2791762868052719757442008 |
| 11 | 1360988846025232489401029220 |
| 12 | 668925190887642335984231235348 |
| 13 | 331039288912491308442251418152952 |
[1,6,1998,722484,291762942,125454173544, 56146411655460,25832836404319152, 12128921727745915062,5783583949613172902394, 2791762868052719757442008, 1360988846025232489401029220, 668925190887642335984231235348, 331039288912491308442251418152952] |