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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 203 |
| 3 | 20 |
| 4 | 467 |
| 5 | 2353 |
| 6 | 1602 |
| 7 | 24272 |
| 8 | 118439 |
| 9 | 372820 |
| 10 | 3857775 |
| 11 | 22638601 |
| 12 | 135423787 |
| 13 | 1109353612 |
| 14 | 7371311350 |
| 15 | 51327931415 |
| 16 | 387280908485 |
| 17 | 2703270862580 |
| 18 | 19437454766314 |
| 19 | 142684818408113 |
| 20 | 1015214265364529 |
| 21 | 7343824393757918 |
[21,203,20,467,2353,1602,24272,118439,372820, 3857775,22638601,135423787,1109353612,7371311350, 51327931415,387280908485,2703270862580, 19437454766314,142684818408113,1015214265364529, 7343824393757918] |