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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 60 |
| 2 | 1770 |
| 3 | 34220 |
| 4 | 487635 |
| 5 | 5461512 |
| 6 | 50063860 |
| 7 | 386206920 |
| 8 | 2558620845 |
| 9 | 14783142660 |
| 10 | 75394027566 |
| 11 | 342700125300 |
| 12 | 1399358844975 |
| 13 | 5166863427600 |
| 14 | 17345898649800 |
| 15 | 53194089192720 |
| 16 | 149608375854525 |
| 17 | 387221678682300 |
| 18 | 925029565741050 |
| 19 | 2044802197953900 |
[1,60,1770,34220,487635,5461512,50063860, 386206920,2558620845,14783142660,75394027566, 342700125300,1399358844975,5166863427600, 17345898649800,53194089192720,149608375854525, 387221678682300,925029565741050,2044802197953900] |