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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 22 |
| 5 | 45 |
| 6 | 90 |
| 7 | 177 |
| 8 | 348 |
| 9 | 684 |
| 10 | 1350 |
| 11 | 2670 |
| 12 | 5298 |
| 13 | 10531 |
| 14 | 20974 |
| 15 | 41815 |
| 16 | 83452 |
| 17 | 166639 |
| 18 | 332926 |
| 19 | 665329 |
| 20 | 1329964 |
| 21 | 2658898 |
| 22 | 5316430 |
| 23 | 10630828 |
| 24 | 21258958 |
| 25 | 42513898 |
| 26 | 85022458 |
| 27 | 170036950 |
| 28 | 340063306 |
| 29 | 680110785 |
| 30 | 1360200510 |
| 31 | 2720369517 |
[1,4,10,22,45,90,177,348,684,1350,2670,5298,10531, 20974,41815,83452,166639,332926,665329,1329964, 2658898,5316430,10630828,21258958,42513898, 85022458,170036950,340063306,680110785,1360200510, 2720369517] |