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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 41 |
| 3 | 414 |
| 4 | 4431 |
| 5 | 48699 |
| 6 | 545076 |
| 7 | 6179444 |
| 8 | 70725241 |
| 9 | 815437894 |
| 10 | 9456840276 |
| 11 | 110196725574 |
| 12 | 1289162119401 |
| 13 | 15131911395879 |
| 14 | 178121845513281 |
| 15 | 2101890841202799 |
| 16 | 24856330289305726 |
| 17 | 294500697587787599 |
| 18 | 3495147445120811176 |
| 19 | 41542892270532317969 |
| 20 | 494440478133277365001 |
[1,4,41,414,4431,48699,545076,6179444,70725241, 815437894,9456840276,110196725574,1289162119401, 15131911395879,178121845513281,2101890841202799, 24856330289305726,294500697587787599, 3495147445120811176,41542892270532317969, 494440478133277365001] |