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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 237 |
| 3 | 245 |
| 4 | 1074 |
| 5 | 4719 |
| 6 | 17224 |
| 7 | 65158 |
| 8 | 261426 |
| 9 | 990387 |
| 10 | 3768844 |
| 11 | 14720334 |
| 12 | 56653017 |
| 13 | 217036116 |
| 14 | 839438654 |
| 15 | 3238254715 |
| 16 | 12452927964 |
| 17 | 48026433042 |
| 18 | 185228062557 |
| 19 | 713410490056 |
| 20 | 2749613319152 |
| 21 | 10600692230546 |
| 22 | 40849824445421 |
[21,237,245,1074,4719,17224,65158,261426,990387, 3768844,14720334,56653017,217036116,839438654, 3238254715,12452927964,48026433042,185228062557, 713410490056,2749613319152,10600692230546, 40849824445421] |