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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 32 |
| 3 | 248 |
| 4 | 1921 |
| 5 | 14892 |
| 6 | 115446 |
| 7 | 894961 |
| 8 | 6937925 |
| 9 | 53784248 |
| 10 | 416946757 |
| 11 | 3232258602 |
| 12 | 25057145775 |
| 13 | 194248243009 |
| 14 | 1505853070853 |
| 15 | 11673688450775 |
| 16 | 90496878270178 |
| 17 | 701550757601700 |
| 18 | 5438568433511460 |
| 19 | 42160921765806133 |
| 20 | 326840297382217310 |
[4,32,248,1921,14892,115446,894961,6937925, 53784248,416946757,3232258602,25057145775, 194248243009,1505853070853,11673688450775, 90496878270178,701550757601700,5438568433511460, 42160921765806133,326840297382217310] |