The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 13 |
| 4 | 66 |
| 5 | 158 |
| 6 | 934 |
| 7 | 2446 |
| 8 | 14567 |
| 9 | 39972 |
| 10 | 240130 |
| 11 | 673665 |
| 12 | 4073862 |
| 13 | 11545686 |
| 14 | 70212506 |
| 15 | 200446066 |
| 16 | 1224207384 |
| 17 | 3512430906 |
| 18 | 21526789216 |
| 19 | 62001340484 |
| 20 | 381049009426 |
| 21 | 1100824791540 |
| 22 | 6780941436208 |
| 23 | 19637801359798 |
| 24 | 121196222602133 |
[0,4,13,66,158,934,2446,14567,39972,240130,673665, 4073862,11545686,70212506,200446066,1224207384, 3512430906,21526789216,62001340484,381049009426, 1100824791540,6780941436208,19637801359798, 121196222602133] |