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| n | a(n) |
|---|---|
| 1 | 22 |
| 2 | 218 |
| 3 | 1838 |
| 4 | 15540 |
| 5 | 132236 |
| 6 | 1126072 |
| 7 | 9588028 |
| 8 | 81634704 |
| 9 | 695055928 |
| 10 | 5917866680 |
| 11 | 50386093544 |
| 12 | 428998916880 |
| 13 | 3652596505952 |
| 14 | 31099055733376 |
| 15 | 264784589835472 |
| 16 | 2254437550085472 |
| 17 | 19194805371407680 |
| 18 | 163429034985577568 |
[22,218,1838,15540,132236,1126072,9588028, 81634704,695055928,5917866680,50386093544, 428998916880,3652596505952,31099055733376, 264784589835472,2254437550085472, 19194805371407680,163429034985577568] |