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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 41 |
| 5 | 338 |
| 6 | 3499 |
| 7 | 42969 |
| 8 | 606351 |
| 9 | 9633640 |
| 10 | 169888025 |
| 11 | 3290314970 |
| 12 | 69409429043 |
| 13 | 1584105116525 |
| 14 | 38894316619948 |
| 15 | 1022411500472240 |
| 16 | 28653072049382809 |
| 17 | 852911635849385778 |
| 18 | 26876978490909421289 |
| 19 | 893929164892155754432 |
| 20 | 31296785296935394097351 |
| 21 | 1150551256823546563078988 |
[1,1,2,7,41,338,3499,42969,606351,9633640, 169888025,3290314970,69409429043,1584105116525, 38894316619948,1022411500472240,28653072049382809, 852911635849385778,26876978490909421289, 893929164892155754432,31296785296935394097351, 1150551256823546563078988] |