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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 51 |
| 3 | 117 |
| 4 | 277 |
| 5 | 3988 |
| 6 | 13869 |
| 7 | 54941 |
| 8 | 427096 |
| 9 | 1946889 |
| 10 | 9366796 |
| 11 | 57663268 |
| 12 | 295969544 |
| 13 | 1539763069 |
| 14 | 8765786966 |
| 15 | 47008512064 |
| 16 | 252662845220 |
| 17 | 1403048644300 |
| 18 | 7643576472481 |
| 19 | 41637425213850 |
| 20 | 229520211886381 |
| 21 | 1257575861723627 |
[3,51,117,277,3988,13869,54941,427096,1946889, 9366796,57663268,295969544,1539763069,8765786966, 47008512064,252662845220,1403048644300, 7643576472481,41637425213850,229520211886381, 1257575861723627] |