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| n | a(n) |
|---|---|
| 1 | 670 |
| 2 | 2498 |
| 3 | 9328 |
| 4 | 35354 |
| 5 | 135254 |
| 6 | 523532 |
| 7 | 2047890 |
| 8 | 8097130 |
| 9 | 32339728 |
| 10 | 130423938 |
| 11 | 530742334 |
| 12 | 2177937580 |
| 13 | 9005319178 |
| 14 | 37492012258 |
| 15 | 157045852768 |
| 16 | 661404560282 |
| 17 | 2798723937382 |
| 18 | 11891816958860 |
| 19 | 50708771987330 |
| 20 | 216898348529434 |
[670,2498,9328,35354,135254,523532,2047890, 8097130,32339728,130423938,530742334,2177937580, 9005319178,37492012258,157045852768,661404560282, 2798723937382,11891816958860,50708771987330, 216898348529434] |