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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 90 |
| 5 | 1530 |
| 6 | 50490 |
| 7 | 3281850 |
| 8 | 423358650 |
| 9 | 108803173050 |
| 10 | 55816027774650 |
| 11 | 57211428469016250 |
| 12 | 117226216933014296250 |
| 13 | 480275810774559571736250 |
| 14 | 3934899717675966571235096250 |
| 15 | 64473331874120712269687052056250 |
[1,2,10,90,1530,50490,3281850,423358650, 108803173050,55816027774650,57211428469016250, 117226216933014296250,480275810774559571736250, 3934899717675966571235096250, 64473331874120712269687052056250] |