The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 82 |
| 5 | 339 |
| 6 | 1461 |
| 7 | 6482 |
| 8 | 29384 |
| 9 | 135426 |
| 10 | 632225 |
| 11 | 2981872 |
| 12 | 14180688 |
| 13 | 67895415 |
| 14 | 326899704 |
| 15 | 1581320373 |
| 16 | 7679588620 |
| 17 | 37420701756 |
| 18 | 182865431382 |
| 19 | 895826999202 |
| 20 | 4397905180052 |
| 21 | 21630991920019 |
| 22 | 106564981184354 |
| 23 | 525743716070770 |
| 24 | 2597058893692578 |
| 25 | 12843243481920950 |
| 26 | 63576790918965557 |
| 27 | 314997058625176355 |
[1,2,6,21,82,339,1461,6482,29384,135426,632225, 2981872,14180688,67895415,326899704,1581320373, 7679588620,37420701756,182865431382,895826999202, 4397905180052,21630991920019,106564981184354, 525743716070770,2597058893692578, 12843243481920950,63576790918965557, 314997058625176355] |