The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 36 |
| 6 | 110 |
| 7 | 374 |
| 8 | 1404 |
| 9 | 5750 |
| 10 | 25419 |
| 11 | 120325 |
| 12 | 606210 |
| 13 | 3234618 |
| 14 | 18202851 |
| 15 | 107647893 |
| 16 | 666903189 |
| 17 | 4316424771 |
| 18 | 29116689197 |
| 19 | 204259773724 |
| 20 | 1487336089532 |
| 21 | 11221857590608 |
| 22 | 87591879539120 |
| 23 | 706286859093554 |
| 24 | 5875489876724901 |
| 25 | 50364717424939105 |
| 26 | 444367708336858660 |
[1,1,2,5,13,36,110,374,1404,5750,25419,120325, 606210,3234618,18202851,107647893,666903189, 4316424771,29116689197,204259773724,1487336089532, 11221857590608,87591879539120,706286859093554, 5875489876724901,50364717424939105, 444367708336858660] |