The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 26 |
| 4 | 150 |
| 5 | 925 |
| 6 | 5967 |
| 7 | 39772 |
| 8 | 271758 |
| 9 | 1893431 |
| 10 | 13400897 |
| 11 | 96078789 |
| 12 | 696333585 |
| 13 | 5093266409 |
| 14 | 37549674939 |
| 15 | 278739057687 |
| 16 | 2081637677823 |
| 17 | 15628794649931 |
| 18 | 117897848681271 |
| 19 | 893167062280029 |
| 20 | 6792410218680749 |
| 21 | 51835002735642287 |
| 22 | 396821349652564273 |
[1,1,5,26,150,925,5967,39772,271758,1893431, 13400897,96078789,696333585,5093266409, 37549674939,278739057687,2081637677823, 15628794649931,117897848681271,893167062280029, 6792410218680749,51835002735642287, 396821349652564273] |