The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 46 |
| 6 | 165 |
| 7 | 651 |
| 8 | 2771 |
| 9 | 12638 |
| 10 | 61397 |
| 11 | 315507 |
| 12 | 1708420 |
| 13 | 9693168 |
| 14 | 57360909 |
| 15 | 352099643 |
| 16 | 2229930365 |
| 17 | 14494768448 |
| 18 | 96229497555 |
| 19 | 649761232948 |
| 20 | 4446218110646 |
| 21 | 30745322129155 |
| 22 | 214353097904732 |
| 23 | 1504152530715607 |
| 24 | 10609439744527674 |
| 25 | 75146372454242527 |
[1,1,2,5,14,46,165,651,2771,12638,61397,315507, 1708420,9693168,57360909,352099643,2229930365, 14494768448,96229497555,649761232948, 4446218110646,30745322129155,214353097904732, 1504152530715607,10609439744527674, 75146372454242527] |