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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 21 |
| 4 | 261 |
| 5 | 4833 |
| 6 | 120303 |
| 7 | 3778029 |
| 8 | 143531433 |
| 9 | 6404711553 |
| 10 | 328447585179 |
| 11 | 19037277446949 |
| 12 | 1230842669484717 |
| 13 | 87829738967634849 |
| 14 | 6856701559496841159 |
| 15 | 581343578623728854397 |
| 16 | 53196439113856500195537 |
| 17 | 5225543459274294130169601 |
| 18 | 548468830470032135590262067 |
| 19 | 61258398893626609968686844597 |
[1,1,3,21,261,4833,120303,3778029,143531433, 6404711553,328447585179,19037277446949, 1230842669484717,87829738967634849, 6856701559496841159,581343578623728854397, 53196439113856500195537,5225543459274294130169601, 548468830470032135590262067, 61258398893626609968686844597] |