The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 31 |
| 3 | 21 |
| 4 | 77 |
| 5 | 336 |
| 6 | 1041 |
| 7 | 3676 |
| 8 | 12970 |
| 9 | 45311 |
| 10 | 162322 |
| 11 | 581460 |
| 12 | 2074761 |
| 13 | 7425880 |
| 14 | 26606520 |
| 15 | 95200209 |
| 16 | 340938956 |
| 17 | 1221189411 |
| 18 | 4373317686 |
| 19 | 15664416165 |
| 20 | 56107953172 |
| 21 | 200965985895 |
| 22 | 719842577248 |
| 23 | 2578420648657 |
| 24 | 9235682972244 |
[1,31,21,77,336,1041,3676,12970,45311,162322, 581460,2074761,7425880,26606520,95200209, 340938956,1221189411,4373317686,15664416165, 56107953172,200965985895,719842577248, 2578420648657,9235682972244] |