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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 86 |
| 3 | 374 |
| 4 | 1841 |
| 5 | 9037 |
| 6 | 47791 |
| 7 | 255406 |
| 8 | 1432328 |
| 9 | 8145489 |
| 10 | 46701775 |
| 11 | 269741883 |
| 12 | 1568279203 |
| 13 | 9153838956 |
| 14 | 53577605791 |
| 15 | 314145731065 |
| 16 | 1844204380914 |
| 17 | 10835966335712 |
| 18 | 63710021424647 |
| 19 | 374740321237045 |
| 20 | 2204822119962792 |
[21,86,374,1841,9037,47791,255406,1432328,8145489, 46701775,269741883,1568279203,9153838956, 53577605791,314145731065,1844204380914, 10835966335712,63710021424647,374740321237045, 2204822119962792] |