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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 12 |
| 4 | 58 |
| 5 | 598 |
| 6 | 4427 |
| 7 | 26350 |
| 8 | 164148 |
| 9 | 1074794 |
| 10 | 7035874 |
| 11 | 45524948 |
| 12 | 294270860 |
| 13 | 1906419263 |
| 14 | 12357270209 |
| 15 | 80067019748 |
| 16 | 518700090254 |
| 17 | 3360509757482 |
| 18 | 21772676551545 |
| 19 | 141063777857884 |
| 20 | 913934658637407 |
| 21 | 5921269752932641 |
[1,7,12,58,598,4427,26350,164148,1074794,7035874, 45524948,294270860,1906419263,12357270209, 80067019748,518700090254,3360509757482, 21772676551545,141063777857884,913934658637407, 5921269752932641] |