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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 14 |
| 5 | 58 |
| 6 | 302 |
| 7 | 1858 |
| 8 | 13262 |
| 9 | 107698 |
| 10 | 980942 |
| 11 | 9905458 |
| 12 | 109844942 |
| 13 | 1327159858 |
| 14 | 17353902542 |
| 15 | 244180971058 |
| 16 | 3678842132942 |
| 17 | 59089527531058 |
| 18 | 1007972756756942 |
| 19 | 18199148360427058 |
| 20 | 346736152866068942 |
[1,2,4,14,58,302,1858,13262,107698,980942,9905458, 109844942,1327159858,17353902542,244180971058, 3678842132942,59089527531058,1007972756756942, 18199148360427058,346736152866068942] |