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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 36 |
| 3 | 210 |
| 4 | 1206 |
| 5 | 6834 |
| 6 | 38322 |
| 7 | 213042 |
| 8 | 1175850 |
| 9 | 6450402 |
| 10 | 35200458 |
| 11 | 191222994 |
| 12 | 1034688474 |
| 13 | 5579060610 |
| 14 | 29989217034 |
| 15 | 160755450546 |
| 16 | 859578198138 |
| 17 | 4585950964578 |
| 18 | 24416800390890 |
| 19 | 129760544069778 |
| 20 | 688431162218202 |
[6,36,210,1206,6834,38322,213042,1175850,6450402, 35200458,191222994,1034688474,5579060610, 29989217034,160755450546,859578198138, 4585950964578,24416800390890,129760544069778, 688431162218202] |