| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 35 |
| 4 | 294 |
| 5 | 2772 |
| 6 | 28314 |
| 7 | 306735 |
| 8 | 3476330 |
| 9 | 40831076 |
| 10 | 493684828 |
| 11 | 6114096716 |
| 12 | 77266057400 |
| 13 | 993420738000 |
| 14 | 12964140630900 |
| 15 | 171393565105575 |
| 16 | 2291968851019650 |
| 17 | 30961684478686500 |
| 18 | 422056646314726500 |
[1,5,35,294,2772,28314,306735,3476330,40831076, 493684828,6114096716,77266057400,993420738000, 12964140630900,171393565105575,2291968851019650, 30961684478686500,422056646314726500] |