The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 11 |
| 4 | 50 |
| 5 | 216 |
| 6 | 1062 |
| 7 | 5457 |
| 8 | 28088 |
| 9 | 147686 |
| 10 | 792716 |
| 11 | 4303036 |
| 12 | 23587816 |
| 13 | 130552984 |
| 14 | 728316462 |
| 15 | 4090107939 |
| 16 | 23106799662 |
| 17 | 131234374020 |
| 18 | 748839982332 |
| 19 | 4290960328482 |
| 20 | 24681334371228 |
| 21 | 142454368143300 |
| 22 | 824786385860748 |
[1,1,2,11,50,216,1062,5457,28088,147686,792716, 4303036,23587816,130552984,728316462,4090107939, 23106799662,131234374020,748839982332, 4290960328482,24681334371228,142454368143300, 824786385860748] |