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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 16 |
| 3 | 92 |
| 4 | 556 |
| 5 | 3332 |
| 6 | 19996 |
| 7 | 119972 |
| 8 | 719836 |
| 9 | 4319012 |
| 10 | 25914076 |
| 11 | 155484452 |
| 12 | 932906716 |
| 13 | 5597440292 |
| 14 | 33584641756 |
| 15 | 201507850532 |
| 16 | 1209047103196 |
| 17 | 7254282619172 |
| 18 | 43525695715036 |
| 19 | 261154174290212 |
| 20 | 1566925045741276 |
[2,16,92,556,3332,19996,119972,719836,4319012, 25914076,155484452,932906716,5597440292, 33584641756,201507850532,1209047103196, 7254282619172,43525695715036,261154174290212, 1566925045741276] |