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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 16 |
| 3 | 61 |
| 4 | 660 |
| 5 | 6107 |
| 6 | 37225 |
| 7 | 349391 |
| 8 | 2557552 |
| 9 | 19278771 |
| 10 | 156296532 |
| 11 | 1179331101 |
| 12 | 9153019452 |
| 13 | 71351814352 |
| 14 | 548547053971 |
| 15 | 4256314971079 |
| 16 | 32951502011481 |
| 17 | 254689445056816 |
| 18 | 1972727580974503 |
| 19 | 15263452717088948 |
| 20 | 118105432842264754 |
[1,16,61,660,6107,37225,349391,2557552,19278771, 156296532,1179331101,9153019452,71351814352, 548547053971,4256314971079,32951502011481, 254689445056816,1972727580974503, 15263452717088948,118105432842264754] |