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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 14 |
| 3 | 118 |
| 4 | 919 |
| 5 | 7562 |
| 6 | 64721 |
| 7 | 563496 |
| 8 | 4956889 |
| 9 | 43888821 |
| 10 | 390006208 |
| 11 | 3473152825 |
| 12 | 30971163817 |
| 13 | 276395100537 |
| 14 | 2467754655037 |
| 15 | 22039067141607 |
| 16 | 196858997624033 |
| 17 | 1758568575970935 |
| 18 | 15710437359317486 |
| 19 | 140356344121017589 |
[4,14,118,919,7562,64721,563496,4956889,43888821, 390006208,3473152825,30971163817,276395100537, 2467754655037,22039067141607,196858997624033, 1758568575970935,15710437359317486, 140356344121017589] |