| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 40 |
| 2 | 1601 |
| 3 | 64080 |
| 4 | 2564801 |
| 5 | 102656120 |
| 6 | 4108809601 |
| 7 | 164455040160 |
| 8 | 6582310416001 |
| 9 | 263456871680200 |
| 10 | 10544857177624001 |
| 11 | 422057743976640240 |
| 12 | 16892854616243233601 |
| 13 | 676136242393705984280 |
| 14 | 27062342550364482604801 |
| 15 | 1083169838256973010176320 |
[1,40,1601,64080,2564801,102656120,4108809601, 164455040160,6582310416001,263456871680200, 10544857177624001,422057743976640240, 16892854616243233601,676136242393705984280, 27062342550364482604801,1083169838256973010176320] |