The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 9 |
| 3 | 44 |
| 4 | 178 |
| 5 | 689 |
| 6 | 2723 |
| 7 | 11304 |
| 8 | 49772 |
| 9 | 232657 |
| 10 | 1151781 |
| 11 | 6018628 |
| 12 | 33087022 |
| 13 | 190780001 |
| 14 | 1150653679 |
| 15 | 7241710656 |
| 16 | 47454745496 |
| 17 | 323154695841 |
| 18 | 2282779990113 |
| 19 | 16700904488284 |
| 20 | 126356632389834 |
| 21 | 987303454928465 |
| 22 | 7957133905608283 |
| 23 | 66071772829246808 |
[0,1,9,44,178,689,2723,11304,49772,232657,1151781, 6018628,33087022,190780001,1150653679,7241710656, 47454745496,323154695841,2282779990113, 16700904488284,126356632389834,987303454928465, 7957133905608283,66071772829246808] |