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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 93 |
| 4 | 681 |
| 5 | 5691 |
| 6 | 53079 |
| 7 | 544053 |
| 8 | 6058545 |
| 9 | 72652179 |
| 10 | 931542207 |
| 11 | 12697268205 |
| 12 | 183092096409 |
| 13 | 2781622021899 |
| 14 | 44367455166279 |
| 15 | 740692876276101 |
| 16 | 12907778812456929 |
| 17 | 234245590139848611 |
| 18 | 4417503444286366191 |
| 19 | 86405523372046968573 |
| 20 | 1749924601146886483977 |
[1,3,15,93,681,5691,53079,544053,6058545,72652179, 931542207,12697268205,183092096409,2781622021899, 44367455166279,740692876276101,12907778812456929, 234245590139848611,4417503444286366191, 86405523372046968573,1749924601146886483977] |