The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 11 |
| 6 | 28 |
| 7 | 79 |
| 8 | 215 |
| 9 | 629 |
| 10 | 1809 |
| 11 | 5426 |
| 12 | 16470 |
| 13 | 50317 |
| 14 | 155322 |
| 15 | 483924 |
| 16 | 1521732 |
| 17 | 4822068 |
| 18 | 15360504 |
| 19 | 49144119 |
| 20 | 158049374 |
| 21 | 510824766 |
| 22 | 1657541406 |
| 23 | 5396486955 |
| 24 | 17626155846 |
| 25 | 57754129486 |
| 26 | 189807753894 |
| 27 | 625506513608 |
| 28 | 2066420369017 |
| 29 | 6842171033524 |
[1,1,1,2,5,11,28,79,215,629,1809,5426,16470,50317, 155322,483924,1521732,4822068,15360504,49144119, 158049374,510824766,1657541406,5396486955, 17626155846,57754129486,189807753894,625506513608, 2066420369017,6842171033524] |