The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 12 |
| 5 | 30 |
| 6 | 82 |
| 7 | 198 |
| 8 | 533 |
| 9 | 1459 |
| 10 | 4039 |
| 11 | 11634 |
| 12 | 34095 |
| 13 | 102520 |
| 14 | 316456 |
| 15 | 995709 |
| 16 | 3215552 |
| 17 | 10591412 |
| 18 | 35633438 |
| 19 | 122499429 |
| 20 | 428988392 |
| 21 | 1532929060 |
| 22 | 5579867442 |
| 23 | 20677066725 |
| 24 | 78027003260 |
| 25 | 299413756170 |
| 26 | 1168536196157 |
| 27 | 4635420192861 |
| 28 | 18678567555721 |
| 29 | 76451691937279 |
| 30 | 317625507668759 |
[1,1,2,6,12,30,82,198,533,1459,4039,11634,34095, 102520,316456,995709,3215552,10591412,35633438, 122499429,428988392,1532929060,5579867442, 20677066725,78027003260,299413756170, 1168536196157,4635420192861,18678567555721, 76451691937279,317625507668759] |