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| n | a(n) |
|---|---|
| 1 | 31 |
| 2 | 129 |
| 3 | 542 |
| 4 | 2297 |
| 5 | 9747 |
| 6 | 41430 |
| 7 | 176119 |
| 8 | 748937 |
| 9 | 3184790 |
| 10 | 13544009 |
| 11 | 57598363 |
| 12 | 244951310 |
| 13 | 1041712935 |
| 14 | 4430144161 |
| 15 | 18840275454 |
| 16 | 80122960441 |
| 17 | 340742738947 |
| 18 | 1449093190086 |
| 19 | 6162628517847 |
| 20 | 26208108810425 |
| 21 | 111456491689126 |
[31,129,542,2297,9747,41430,176119,748937,3184790, 13544009,57598363,244951310,1041712935,4430144161, 18840275454,80122960441,340742738947, 1449093190086,6162628517847,26208108810425, 111456491689126] |