The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 85 |
| 6 | 315 |
| 7 | 1055 |
| 8 | 4012 |
| 9 | 13985 |
| 10 | 54082 |
| 11 | 193919 |
| 12 | 757327 |
| 13 | 2767218 |
| 14 | 10875615 |
| 15 | 40282189 |
| 16 | 159004452 |
| 17 | 594976144 |
| 18 | 2355738462 |
| 19 | 8884815803 |
| 20 | 35256788279 |
| 21 | 133810866365 |
| 22 | 531868815609 |
| 23 | 2028932703003 |
| 24 | 8074680435556 |
| 25 | 30932776387067 |
| 26 | 123224123759839 |
| 27 | 473724053938601 |
| 28 | 1888553495309558 |
[1,1,3,8,28,85,315,1055,4012,13985,54082,193919, 757327,2767218,10875615,40282189,159004452, 594976144,2355738462,8884815803,35256788279, 133810866365,531868815609,2028932703003, 8074680435556,30932776387067,123224123759839, 473724053938601,1888553495309558] |