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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 37 |
| 5 | 146 |
| 6 | 772 |
| 7 | 4449 |
| 8 | 30307 |
| 9 | 228605 |
| 10 | 1921464 |
| 11 | 17652327 |
| 12 | 176162548 |
| 13 | 1893738334 |
| 14 | 21806975279 |
| 15 | 267636988052 |
| 16 | 3486370839295 |
| 17 | 48029272657002 |
| 18 | 697542580286159 |
| 19 | 10649954607360119 |
| 20 | 170508064788069346 |
| 21 | 2856122791685125616 |
| 22 | 49951625299057923405 |
[1,3,9,37,146,772,4449,30307,228605,1921464, 17652327,176162548,1893738334,21806975279, 267636988052,3486370839295,48029272657002, 697542580286159,10649954607360119, 170508064788069346,2856122791685125616, 49951625299057923405] |