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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 10 |
| 3 | 630 |
| 4 | 52650 |
| 5 | 165600 |
| 6 | 986310 |
| 7 | 9446031 |
| 8 | 9485190 |
| 9 | 10693000 |
| 10 | 1270004401 |
| 11 | 14214075921 |
| 12 | 140884670790 |
| 13 | 1809702709101 |
| 14 | 4614899724711 |
| 15 | 6766532724546 |
| 16 | 9802814901400 |
| 17 | 10210140486640 |
| 18 | 14287075542460 |
| 19 | 52657436563056 |
| 20 | 98855178542676 |
[1,10,630,52650,165600,986310,9446031,9485190, 10693000,1270004401,14214075921,140884670790, 1809702709101,4614899724711,6766532724546, 9802814901400,10210140486640,14287075542460, 52657436563056,98855178542676] |