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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 21 |
| 2 | 169 |
| 3 | 1101 |
| 4 | 8369 |
| 5 | 64671 |
| 6 | 511957 |
| 7 | 4108671 |
| 8 | 33331889 |
| 9 | 272616609 |
| 10 | 2244091579 |
| 11 | 18568201871 |
| 12 | 154285123493 |
| 13 | 1286408940149 |
| 14 | 10756655080753 |
| 15 | 90159207784161 |
| 16 | 757192897525073 |
| 17 | 6369787770505701 |
| 18 | 53659598197631131 |
| 19 | 452559057596166759 |
[1,21,169,1101,8369,64671,511957,4108671,33331889, 272616609,2244091579,18568201871,154285123493, 1286408940149,10756655080753,90159207784161, 757192897525073,6369787770505701, 53659598197631131,452559057596166759] |