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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 24 |
| 4 | 97 |
| 5 | 390 |
| 6 | 1560 |
| 7 | 6241 |
| 8 | 24966 |
| 9 | 99864 |
| 10 | 399457 |
| 11 | 1597830 |
| 12 | 6391320 |
| 13 | 25565281 |
| 14 | 102261126 |
| 15 | 409044504 |
| 16 | 1636178017 |
| 17 | 6544712070 |
| 18 | 26178848280 |
| 19 | 104715393121 |
| 20 | 418861572486 |
| 21 | 1675446289944 |
| 22 | 6701785159777 |
| 23 | 26807140639110 |
| 24 | 107228562556440 |
[1,6,24,97,390,1560,6241,24966,99864,399457, 1597830,6391320,25565281,102261126,409044504, 1636178017,6544712070,26178848280,104715393121, 418861572486,1675446289944,6701785159777, 26807140639110,107228562556440] |