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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 49 |
| 3 | 336 |
| 4 | 2310 |
| 5 | 15834 |
| 6 | 108402 |
| 7 | 741090 |
| 8 | 5060706 |
| 9 | 34523202 |
| 10 | 235304034 |
| 11 | 1602555906 |
| 12 | 10906971810 |
| 13 | 74188793154 |
| 14 | 504367206882 |
| 15 | 3427339028610 |
| 16 | 23280526483746 |
| 17 | 158079249910722 |
| 18 | 1073053862250594 |
| 19 | 7281968079533826 |
| 20 | 49404973360789410 |
[7,49,336,2310,15834,108402,741090,5060706, 34523202,235304034,1602555906,10906971810, 74188793154,504367206882,3427339028610, 23280526483746,158079249910722,1073053862250594, 7281968079533826,49404973360789410] |