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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 34 |
| 3 | 55 |
| 4 | 377 |
| 5 | 4181 |
| 6 | 17711 |
| 7 | 121393 |
| 8 | 1346269 |
| 9 | 5702887 |
| 10 | 165580141 |
| 11 | 53316291173 |
| 12 | 956722026041 |
| 13 | 2504730781961 |
| 14 | 308061521170129 |
| 15 | 806515533049393 |
| 16 | 14472334024676221 |
| 17 | 1779979416004714189 |
| 18 | 19740274219868223167 |
| 19 | 573147844013817084101 |
| 20 | 10284720757613717413913 |
[21,34,55,377,4181,17711,121393,1346269,5702887, 165580141,53316291173,956722026041,2504730781961, 308061521170129,806515533049393,14472334024676221, 1779979416004714189,19740274219868223167, 573147844013817084101,10284720757613717413913] |