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 | 15 |
| 5 | 46 |
| 6 | 162 |
| 7 | 573 |
| 8 | 2186 |
| 9 | 8411 |
| 10 | 33783 |
| 11 | 136964 |
| 12 | 570345 |
| 13 | 2395284 |
| 14 | 10241316 |
| 15 | 44112212 |
| 16 | 192417802 |
| 17 | 844668469 |
| 18 | 3742462954 |
| 19 | 16672149834 |
| 20 | 74799056643 |
| 21 | 337155007308 |
| 22 | 1528184417633 |
| 23 | 6954558011029 |
| 24 | 31791403631798 |
| 25 | 145834990404475 |
| 26 | 671458714209519 |
| 27 | 3100927196427213 |
| 28 | 14365248430386121 |
[1,1,2,5,15,46,162,573,2186,8411,33783,136964, 570345,2395284,10241316,44112212,192417802, 844668469,3742462954,16672149834,74799056643, 337155007308,1528184417633,6954558011029, 31791403631798,145834990404475,671458714209519, 3100927196427213,14365248430386121] |