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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 34 |
| 3 | 180 |
| 4 | 886 |
| 5 | 4116 |
| 6 | 18334 |
| 7 | 79260 |
| 8 | 335446 |
| 9 | 1398276 |
| 10 | 5765134 |
| 11 | 23581740 |
| 12 | 95900806 |
| 13 | 388345236 |
| 14 | 1567647934 |
| 15 | 6313474620 |
| 16 | 25382710966 |
| 17 | 101917608996 |
| 18 | 408831386734 |
| 19 | 1638809709900 |
| 20 | 6565693949926 |
| 21 | 26294146373556 |
| 22 | 105270707701534 |
| 23 | 421365218399580 |
[6,34,180,886,4116,18334,79260,335446,1398276, 5765134,23581740,95900806,388345236,1567647934, 6313474620,25382710966,101917608996,408831386734, 1638809709900,6565693949926,26294146373556, 105270707701534,421365218399580] |