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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 7 |
| 4 | 31 |
| 5 | 145 |
| 6 | 673 |
| 7 | 3127 |
| 8 | 14527 |
| 9 | 67489 |
| 10 | 313537 |
| 11 | 1456615 |
| 12 | 6767071 |
| 13 | 31438129 |
| 14 | 146053729 |
| 15 | 678529303 |
| 16 | 3152278399 |
| 17 | 14644701505 |
| 18 | 68035641217 |
| 19 | 316076669383 |
| 20 | 1468413601183 |
| 21 | 6821884412881 |
| 22 | 31692778455073 |
| 23 | 147236767058935 |
[1,1,7,31,145,673,3127,14527,67489,313537,1456615, 6767071,31438129,146053729,678529303,3152278399, 14644701505,68035641217,316076669383, 1468413601183,6821884412881,31692778455073, 147236767058935] |