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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 65 |
| 4 | 471 |
| 5 | 3469 |
| 6 | 25747 |
| 7 | 190425 |
| 8 | 1408823 |
| 9 | 10424813 |
| 10 | 77135267 |
| 11 | 570740149 |
| 12 | 4223043591 |
| 13 | 31247282909 |
| 14 | 231205914319 |
| 15 | 1710746473929 |
| 16 | 12658211881263 |
| 17 | 93661059763965 |
| 18 | 693020010391803 |
| 19 | 5127816575062977 |
| 20 | 37941909947454471 |
[1,7,65,471,3469,25747,190425,1408823,10424813, 77135267,570740149,4223043591,31247282909, 231205914319,1710746473929,12658211881263, 93661059763965,693020010391803,5127816575062977, 37941909947454471] |