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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 2 |
| 3 | 6 |
| 4 | 26 |
| 5 | 182 |
| 6 | 1786 |
| 7 | 22870 |
| 8 | 359226 |
| 9 | 6658038 |
| 10 | 141860538 |
| 11 | 3411462102 |
| 12 | 91331548410 |
| 13 | 2692998369270 |
| 14 | 86698082609658 |
| 15 | 3025579919280726 |
| 16 | 113759391284411322 |
| 17 | 4584343174947333366 |
| 18 | 197110924461251852346 |
| 19 | 9006669123611196569046 |
| 20 | 435827319931153165710714 |
[2,2,6,26,182,1786,22870,359226,6658038,141860538, 3411462102,91331548410,2692998369270, 86698082609658,3025579919280726, 113759391284411322,4584343174947333366, 197110924461251852346,9006669123611196569046, 435827319931153165710714] |