| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 10 |
| 6 | 65 |
| 7 | 350 |
| 8 | 1736 |
| 9 | 9030 |
| 10 | 60355 |
| 11 | 561550 |
| 12 | 6183221 |
| 13 | 69469400 |
| 14 | 761767370 |
| 15 | 8239194600 |
| 16 | 91058524831 |
| 17 | 1073790441370 |
| 18 | 13900626022985 |
| 19 | 196759304278250 |
| 20 | 2963381404815566 |
| 21 | 46227649788125190 |
| 22 | 736940002561065325 |
| 23 | 12005645243802471250 |
| 24 | 201482801573414254301 |
[1,0,0,0,1,10,65,350,1736,9030,60355,561550, 6183221,69469400,761767370,8239194600,91058524831, 1073790441370,13900626022985,196759304278250, 2963381404815566,46227649788125190, 736940002561065325,12005645243802471250, 201482801573414254301] |