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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 119 |
| 3 | 1109 |
| 4 | 7833 |
| 5 | 61755 |
| 6 | 455509 |
| 7 | 3437801 |
| 8 | 25528515 |
| 9 | 190243099 |
| 10 | 1412491505 |
| 11 | 10484413673 |
| 12 | 77772795145 |
| 13 | 576515430247 |
| 14 | 4273815283079 |
| 15 | 31666450138863 |
| 16 | 234664439146089 |
| 17 | 1738444321229885 |
| 18 | 12880327740810545 |
| 19 | 95414952005019587 |
[21,119,1109,7833,61755,455509,3437801,25528515, 190243099,1412491505,10484413673,77772795145, 576515430247,4273815283079,31666450138863, 234664439146089,1738444321229885, 12880327740810545,95414952005019587] |