The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 22 |
| 6 | 62 |
| 7 | 184 |
| 8 | 566 |
| 9 | 1779 |
| 10 | 5678 |
| 11 | 18367 |
| 12 | 60091 |
| 13 | 198454 |
| 14 | 660659 |
| 15 | 2214700 |
| 16 | 7469730 |
| 17 | 25330135 |
| 18 | 86308528 |
| 19 | 295349232 |
| 20 | 1014609122 |
| 21 | 3497707471 |
| 22 | 12096300263 |
| 23 | 41955256710 |
| 24 | 145908382056 |
| 25 | 508676792788 |
| 26 | 1777418947825 |
| 27 | 6223737747078 |
| 28 | 21835417474588 |
| 29 | 76747151840311 |
| 30 | 270209860057674 |
| 31 | 952864014673991 |
| 32 | 3365181832760454 |
| 33 | 11901315653535352 |
[1,1,3,8,22,62,184,566,1779,5678,18367,60091, 198454,660659,2214700,7469730,25330135,86308528, 295349232,1014609122,3497707471,12096300263, 41955256710,145908382056,508676792788, 1777418947825,6223737747078,21835417474588, 76747151840311,270209860057674,952864014673991, 3365181832760454,11901315653535352] |