| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 21 |
| 5 | 66 |
| 6 | 210 |
| 7 | 699 |
| 8 | 2387 |
| 9 | 8492 |
| 10 | 31329 |
| 11 | 120034 |
| 12 | 477028 |
| 13 | 1965016 |
| 14 | 8377888 |
| 15 | 36923184 |
| 16 | 167972182 |
| 17 | 787688821 |
| 18 | 3802526173 |
| 19 | 18873118341 |
| 20 | 96195592212 |
| 21 | 502953711022 |
| 22 | 2694740822749 |
| 23 | 14781176429303 |
| 24 | 82931707378322 |
[1,2,7,21,66,210,699,2387,8492,31329,120034, 477028,1965016,8377888,36923184,167972182, 787688821,3802526173,18873118341,96195592212, 502953711022,2694740822749,14781176429303, 82931707378322] |