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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 21 |
| 3 | 246 |
| 4 | 4143 |
| 5 | 91938 |
| 6 | 2543457 |
| 7 | 84476766 |
| 8 | 3278575515 |
| 9 | 145703001450 |
| 10 | 7299102908613 |
| 11 | 407061606983430 |
| 12 | 25016221521245703 |
| 13 | 1679926053870309378 |
| 14 | 122399565517464024009 |
| 15 | 9617404242454811783598 |
| 16 | 810684382032520533507891 |
| 17 | 72976185712308646408856538 |
[1,3,21,246,4143,91938,2543457,84476766, 3278575515,145703001450,7299102908613, 407061606983430,25016221521245703, 1679926053870309378,122399565517464024009, 9617404242454811783598,810684382032520533507891, 72976185712308646408856538] |