| n | a(n) |
|---|---|
| 5 | 1 |
| 6 | 5 |
| 7 | 30 |
| 8 | 175 |
| 9 | 1050 |
| 10 | 6552 |
| 11 | 42630 |
| 12 | 289410 |
| 13 | 2049300 |
| 14 | 15120105 |
| 15 | 116090975 |
| 16 | 926248050 |
| 17 | 7668746540 |
| 18 | 65793760060 |
| 19 | 584151925320 |
| 20 | 5360347320420 |
| 21 | 50776288702215 |
| 22 | 495946245776940 |
| 23 | 4989391837053085 |
| 24 | 51648932225779735 |
| 25 | 549620905409062872 |
[1,5,30,175,1050,6552,42630,289410,2049300, 15120105,116090975,926248050,7668746540, 65793760060,584151925320,5360347320420, 50776288702215,495946245776940,4989391837053085, 51648932225779735,549620905409062872] |