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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 49 |
| 3 | 336 |
| 4 | 2280 |
| 5 | 15324 |
| 6 | 102202 |
| 7 | 677200 |
| 8 | 4462414 |
| 9 | 29265308 |
| 10 | 191134204 |
| 11 | 1243794600 |
| 12 | 8068058218 |
| 13 | 52186113316 |
| 14 | 336696234188 |
| 15 | 2167362918200 |
| 16 | 13922979926042 |
| 17 | 89273834257404 |
| 18 | 571453869667592 |
| 19 | 3652311182519800 |
| 20 | 23309932135990218 |
[7,49,336,2280,15324,102202,677200,4462414, 29265308,191134204,1243794600,8068058218, 52186113316,336696234188,2167362918200, 13922979926042,89273834257404,571453869667592, 3652311182519800,23309932135990218] |