The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 6 |
| 3 | 45 |
| 4 | 454 |
| 5 | 5907 |
| 6 | 94518 |
| 7 | 1795849 |
| 8 | 39508686 |
| 9 | 987717159 |
| 10 | 27656080462 |
| 11 | 857338494333 |
| 12 | 29149508807334 |
| 13 | 1078531825871371 |
| 14 | 43141273034854854 |
| 15 | 1855074740498758737 |
| 16 | 85333438062942901918 |
| 17 | 4181338465084202193999 |
| 18 | 217429600184378514087966 |
[0,1,6,45,454,5907,94518,1795849,39508686, 987717159,27656080462,857338494333,29149508807334, 1078531825871371,43141273034854854, 1855074740498758737,85333438062942901918, 4181338465084202193999,217429600184378514087966] |