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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 6 |
| 6 | 24 |
| 7 | 97 |
| 8 | 402 |
| 9 | 1637 |
| 10 | 6759 |
| 11 | 28259 |
| 12 | 119890 |
| 13 | 517121 |
| 14 | 2271860 |
| 15 | 10176660 |
| 16 | 46541024 |
| 17 | 217511951 |
| 18 | 1039651295 |
| 19 | 5084972068 |
| 20 | 25458149446 |
| 21 | 130480742790 |
| 22 | 684550272269 |
| 23 | 3675258986639 |
| 24 | 20184618368312 |
| 25 | 113340974676578 |
| 26 | 650343587802644 |
[1,6,24,97,402,1637,6759,28259,119890,517121, 2271860,10176660,46541024,217511951,1039651295, 5084972068,25458149446,130480742790,684550272269, 3675258986639,20184618368312,113340974676578, 650343587802644] |