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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 7 |
| 2 | 30 |
| 3 | 155 |
| 4 | 946 |
| 5 | 6687 |
| 6 | 53822 |
| 7 | 486355 |
| 8 | 4877250 |
| 9 | 53759351 |
| 10 | 646098622 |
| 11 | 8409146187 |
| 12 | 117836551730 |
| 13 | 1768850337295 |
| 14 | 28318532194206 |
| 15 | 481652022466307 |
| 16 | 8673291031865602 |
| 17 | 164849403644999655 |
| 18 | 3297954931572397790 |
| 19 | 69274457019123638011 |
| 20 | 1524368720086682440242 |
[2,7,30,155,946,6687,53822,486355,4877250, 53759351,646098622,8409146187,117836551730, 1768850337295,28318532194206,481652022466307, 8673291031865602,164849403644999655, 3297954931572397790,69274457019123638011, 1524368720086682440242] |