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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 17 |
| 6 | 39 |
| 7 | 181 |
| 8 | 1975 |
| 9 | 28231 |
| 10 | 443863 |
| 11 | 9105701 |
| 12 | 306959063 |
| 13 | 15386456557 |
| 14 | 1024328375043 |
| 15 | 94252026378527 |
[1,1,1,5,17,39,181,1975,28231,443863,9105701, 306959063,15386456557,1024328375043, 94252026378527] |