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 | 14 |
| 6 | 44 |
| 7 | 153 |
| 8 | 584 |
| 9 | 2414 |
| 10 | 10732 |
| 11 | 50909 |
| 12 | 256198 |
| 13 | 1360645 |
| 14 | 7593530 |
| 15 | 44366458 |
| 16 | 270517289 |
| 17 | 1716555943 |
| 18 | 11308051214 |
| 19 | 77170484915 |
| 20 | 544525867544 |
| 21 | 3965944595335 |
| 22 | 29769162604337 |
| 23 | 229970873746105 |
| 24 | 1826057472681595 |
| 25 | 14886348784740516 |
[1,1,1,2,5,14,44,153,584,2414,10732,50909,256198, 1360645,7593530,44366458,270517289,1716555943, 11308051214,77170484915,544525867544, 3965944595335,29769162604337,229970873746105, 1826057472681595,14886348784740516] |