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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 16 |
| 5 | 117 |
| 6 | 1185 |
| 7 | 16856 |
| 8 | 334597 |
| 9 | 9263497 |
| 10 | 360493767 |
| 11 | 19836684505 |
| 12 | 1547142671748 |
| 13 | 171456480498151 |
| 14 | 27060184630906514 |
| 15 | 6089195353964497464 |
| 16 | 1955550547239382775017 |
| 17 | 897232469707513867626376 |
| 18 | 588505259787507511336381953 |
| 19 | 552133036731399028180043225074 |
[1,1,1,3,16,117,1185,16856,334597,9263497, 360493767,19836684505,1547142671748, 171456480498151,27060184630906514, 6089195353964497464,1955550547239382775017, 897232469707513867626376, 588505259787507511336381953, 552133036731399028180043225074] |