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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 25 |
| 3 | 210 |
| 4 | 1881 |
| 5 | 17303 |
| 6 | 162214 |
| 7 | 1540710 |
| 8 | 14776281 |
| 9 | 142774455 |
| 10 | 1387743525 |
| 11 | 13553773500 |
| 12 | 132906406950 |
| 13 | 1307654814222 |
| 14 | 12902933709922 |
| 15 | 127632756058610 |
| 16 | 1265251299930585 |
| 17 | 12566655467547195 |
| 18 | 125025126985317013 |
| 19 | 1245750306517239978 |
| 20 | 12429515281592007781 |
[1,3,25,210,1881,17303,162214,1540710,14776281, 142774455,1387743525,13553773500,132906406950, 1307654814222,12902933709922,127632756058610, 1265251299930585,12566655467547195, 125025126985317013,1245750306517239978, 12429515281592007781] |