The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 96 |
| 6 | 339 |
| 7 | 1262 |
| 8 | 4910 |
| 9 | 18378 |
| 10 | 72680 |
| 11 | 289633 |
| 12 | 1147306 |
| 13 | 4619304 |
| 14 | 18857624 |
| 15 | 76773467 |
| 16 | 314714055 |
| 17 | 1301446478 |
| 18 | 5398971560 |
| 19 | 22414470746 |
| 20 | 93653492226 |
| 21 | 392944405090 |
| 22 | 1648562424132 |
| 23 | 6942568079795 |
| 24 | 29355972489589 |
| 25 | 124163462054611 |
| 26 | 526313154372409 |
| 27 | 2238070666091934 |
| 28 | 9526155039343081 |
[1,1,3,8,28,96,339,1262,4910,18378,72680,289633, 1147306,4619304,18857624,76773467,314714055, 1301446478,5398971560,22414470746,93653492226, 392944405090,1648562424132,6942568079795, 29355972489589,124163462054611,526313154372409, 2238070666091934,9526155039343081] |