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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 10 |
| 4 | 130 |
| 5 | 2100 |
| 6 | 40950 |
| 7 | 943740 |
| 8 | 25269300 |
| 9 | 774635400 |
| 10 | 26836251750 |
| 11 | 1038607069500 |
| 12 | 44448725821500 |
| 13 | 2084869401615000 |
| 14 | 106355178306877500 |
| 15 | 5861473946222895000 |
| 16 | 346999395775257225000 |
| 17 | 21956626245257906202000 |
| 18 | 1478562610889805715023750 |
| 19 | 105561794005139231136877500 |
| 20 | 7963731010308915234880987500 |
| 21 | 632966979266333111428303275000 |
| 22 | 52862553418201438508049805852500 |
[1,10,130,2100,40950,943740,25269300,774635400, 26836251750,1038607069500,44448725821500, 2084869401615000,106355178306877500, 5861473946222895000,346999395775257225000, 21956626245257906202000,1478562610889805715023750, 105561794005139231136877500, 7963731010308915234880987500, 632966979266333111428303275000, 52862553418201438508049805852500] |