| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 28 |
| 5 | 204 |
| 6 | 2344 |
| 7 | 43160 |
| 8 | 1291952 |
| 9 | 63647664 |
| 10 | 5218320672 |
| 11 | 719221578080 |
| 12 | 168115994031040 |
| 13 | 67159892835119296 |
| 14 | 46166133463916209792 |
| 15 | 54941957091151982047616 |
| 16 | 113826217192695041078973184 |
[1,1,2,6,28,204,2344,43160,1291952,63647664, 5218320672,719221578080,168115994031040, 67159892835119296,46166133463916209792, 54941957091151982047616, 113826217192695041078973184] |