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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 7 |
| 4 | 12 |
| 5 | 22 |
| 6 | 39 |
| 7 | 69 |
| 8 | 122 |
| 9 | 217 |
| 10 | 386 |
| 11 | 687 |
| 12 | 1224 |
| 13 | 2181 |
| 14 | 3883 |
| 15 | 6910 |
| 16 | 12305 |
| 17 | 21906 |
| 18 | 38991 |
| 19 | 69421 |
| 20 | 123609 |
| 21 | 220110 |
| 22 | 391929 |
| 23 | 697931 |
| 24 | 1242873 |
| 25 | 2213237 |
| 26 | 3941323 |
| 27 | 7018445 |
| 28 | 12497917 |
| 29 | 22255832 |
| 30 | 39632383 |
| 31 | 70576606 |
| 32 | 125680814 |
| 33 | 223808756 |
[2,4,7,12,22,39,69,122,217,386,687,1224,2181,3883, 6910,12305,21906,38991,69421,123609,220110,391929, 697931,1242873,2213237,3941323,7018445,12497917, 22255832,39632383,70576606,125680814,223808756] |