The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 32 |
| 5 | 112 |
| 6 | 411 |
| 7 | 1590 |
| 8 | 6222 |
| 9 | 25025 |
| 10 | 101745 |
| 11 | 419657 |
| 12 | 1754602 |
| 13 | 7393290 |
| 14 | 31469686 |
| 15 | 134868306 |
| 16 | 581903908 |
| 17 | 2526957737 |
| 18 | 11027258271 |
| 19 | 48371185519 |
| 20 | 213096893682 |
| 21 | 942519761900 |
| 22 | 4184701749395 |
| 23 | 18640405723677 |
| 24 | 83297501176210 |
| 25 | 373304564910582 |
| 26 | 1677434742864887 |
| 27 | 7556698317628017 |
| 28 | 34120679699125974 |
[1,1,3,9,32,112,411,1590,6222,25025,101745,419657, 1754602,7393290,31469686,134868306,581903908, 2526957737,11027258271,48371185519,213096893682, 942519761900,4184701749395,18640405723677, 83297501176210,373304564910582,1677434742864887, 7556698317628017,34120679699125974] |