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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 7 |
| 2 | 43 |
| 3 | 308 |
| 4 | 15443 |
| 5 | 108409 |
| 6 | 665897 |
| 7 | 4769688 |
| 8 | 239150297 |
| 9 | 1678821767 |
| 10 | 10312080899 |
| 11 | 73863388060 |
| 12 | 3703481483899 |
| 13 | 25998233775353 |
| 14 | 159692884136017 |
| 15 | 1143848422727472 |
| 16 | 57352114020509617 |
| 17 | 402608646566294791 |
| 18 | 2473003993418278363 |
| 19 | 17713636600494243332 |
[1,7,43,308,15443,108409,665897,4769688,239150297, 1678821767,10312080899,73863388060,3703481483899, 25998233775353,159692884136017,1143848422727472, 57352114020509617,402608646566294791, 2473003993418278363,17713636600494243332] |