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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 438 |
| 3 | 9516 |
| 4 | 201960 |
| 5 | 4299802 |
| 6 | 91513161 |
| 7 | 1948262831 |
| 8 | 41475009100 |
| 9 | 882920599454 |
| 10 | 18795714385533 |
| 11 | 400125250527550 |
| 12 | 8517908622924528 |
| 13 | 181330147341356981 |
| 14 | 3860175542316616321 |
| 15 | 82175828913427711206 |
| 16 | 1749367816354069818496 |
[21,438,9516,201960,4299802,91513161,1948262831, 41475009100,882920599454,18795714385533, 400125250527550,8517908622924528, 181330147341356981,3860175542316616321, 82175828913427711206,1749367816354069818496] |