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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 30 |
| 3 | 272 |
| 4 | 2227 |
| 5 | 18205 |
| 6 | 150352 |
| 7 | 1240541 |
| 8 | 10232500 |
| 9 | 84410206 |
| 10 | 696309062 |
| 11 | 5743948074 |
| 12 | 47382634074 |
| 13 | 390866061898 |
| 14 | 3224309862212 |
| 15 | 26597791554069 |
| 16 | 219408975139223 |
| 17 | 1809935922730538 |
| 18 | 14930419523386359 |
| 19 | 123163159741496460 |
[2,30,272,2227,18205,150352,1240541,10232500, 84410206,696309062,5743948074,47382634074, 390866061898,3224309862212,26597791554069, 219408975139223,1809935922730538, 14930419523386359,123163159741496460] |