| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 51 |
| 4 | 807 |
| 5 | 17445 |
| 6 | 479565 |
| 7 | 16019955 |
| 8 | 630301455 |
| 9 | 28552506885 |
| 10 | 1463744449125 |
| 11 | 83780913568275 |
| 12 | 5296205435649975 |
| 13 | 366478026602012325 |
| 14 | 27552067849812030525 |
| 15 | 2236327624673777509875 |
| 16 | 194908916445067162713375 |
| 17 | 18154937081288124469477125 |
| 18 | 1799824448875247911270279125 |
[1,1,5,51,807,17445,479565,16019955,630301455, 28552506885,1463744449125,83780913568275, 5296205435649975,366478026602012325, 27552067849812030525,2236327624673777509875, 194908916445067162713375, 18154937081288124469477125, 1799824448875247911270279125] |